Annual report pursuant to Section 13 and 15(d)

Consolidated Schedule of Investments In and Advances to Affiliates (Details)

v3.22.4
Consolidated Schedule of Investments In and Advances to Affiliates (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Schedule of Investments [Line Items]      
Amount of Unrealized Gain/(Loss) $ 24,816 $ 135,624 $ (5,622)
Control investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) (5,822) 6,494  
Amount of Unrealized Gain/(Loss) 56,682 99,420  
Amount of Interest, Fees or Dividends Credited to Income 155,967 122,277  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,489,257 1,113,725  
Gross Additions 488,176 592,022  
Gross Reductions 268,138 216,490  
Ending balance 1,703,172 1,489,257 1,113,725
Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) (3,319) 17,181  
Amount of Unrealized Gain/(Loss) 10,314 21,989  
Amount of Interest, Fees or Dividends Credited to Income 54,963 51,278  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 549,214 366,301  
Gross Additions 157,996 336,505  
Gross Reductions 104,813 165,855  
Ending balance 618,359 549,214 366,301
Investment, Identifier [Axis]: 2717 MH, L.P., LP Interests (2717 HPP-MS, L.P.) | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 250  
Gross Additions 248 0  
Gross Reductions 0 250  
Ending balance 248 0 250
Investment, Identifier [Axis]: 2717 MH, L.P., LP Interests (2717 MH, L.P.) | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 2,389 1,165  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,971 2,702  
Gross Additions 3,581 1,269  
Gross Reductions 0 0  
Ending balance 7,552 3,971 2,702
Investment, Identifier [Axis]: AAC Holdings, Inc., Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (2,079) (1,069)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,079 3,148  
Gross Additions 0 0  
Gross Reductions 2,079 1,069  
Ending balance $ 0 $ 2,079 3,148
Investment, Identifier [Axis]: AAC Holdings, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 18.00% [1] 18.00% [2]  
PIK Rate 18.00% [1] 8.00% [2]  
Investment, Identifier [Axis]: AAC Holdings, Inc., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 18.00% 18.00%  
PIK Rate 18.00% 8.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 178 (217)  
Amount of Interest, Fees or Dividends Credited to Income 2,032 1,817  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,794 9,187  
Gross Additions 1,756 1,095  
Gross Reductions 0 488  
Ending balance 11,550 9,794 9,187
Investment, Identifier [Axis]: AAC Holdings, Inc., Warrants | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (1,940) (998)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,940 2,938  
Gross Additions 0 0  
Gross Reductions 1,940 998  
Ending balance $ 0 $ 1,940 2,938
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.00%    
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.20%    
Spread [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.58%    
Spread [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: ADS Tactical, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.14% [1],[5] 6.75% [2],[7]  
Spread 5.75% [1],[5] 5.75% [2],[7]  
Investment, Identifier [Axis]: AFG Capital Group, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 1,660 1,930  
Amount of Interest, Fees or Dividends Credited to Income 200 200  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,740 5,810  
Gross Additions 1,660 1,930  
Gross Reductions 0 0  
Ending balance 9,400 $ 7,740 5,810
Investment, Identifier [Axis]: AFG Capital Group, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   10.00%  
Investment, Identifier [Axis]: AFG Capital Group, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   10.00%  
Amount of Realized Gain/(Loss) 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 2 31  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 144 491  
Gross Additions 0 0  
Gross Reductions 144 347  
Ending balance $ 0 144 491
Investment, Identifier [Axis]: AMEREQUIP LLC., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 7.40%    
Investment, Identifier [Axis]: AMEREQUIP LLC., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.72%    
Spread [3],[4],[5] 7.40%    
Investment, Identifier [Axis]: ASC Interests, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 0  
Amount of Unrealized Gain/(Loss) 80 (400)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 720 1,120  
Gross Additions 80 0  
Gross Reductions 0 400  
Ending balance 800 $ 720 1,120
Investment, Identifier [Axis]: ASC Interests, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   261  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,836 1,715  
Gross Additions   121  
Gross Reductions   0  
Ending balance   $ 1,836 1,715
Investment, Identifier [Axis]: ASC Interests, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Investment, Identifier [Axis]: ASC Interests, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 36    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 200    
Gross Additions 230    
Gross Reductions 30    
Ending balance $ 400 $ 200  
Investment, Identifier [Axis]: ASC Interests, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Investment, Identifier [Axis]: ASC Interests, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 266    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,636    
Gross Additions 13    
Gross Reductions 0    
Ending balance 1,649 $ 1,636  
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (733)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 4,894 3,200  
Gross Additions   4,894  
Gross Reductions   3,200  
Ending balance   4,894 3,200
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Preferred Member Units 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 14.13%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 0  
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Preferred Member Units 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (1,390)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,894    
Gross Additions 0    
Gross Reductions 1,390    
Ending balance 3,504 $ 4,894  
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   10.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   691  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 4,736 4,873  
Gross Additions   153  
Gross Reductions   290  
Ending balance   4,736 4,873
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 10.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 6    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (4)    
Gross Additions 1    
Gross Reductions 0    
Ending balance $ (3) (4)  
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 14.13%    
Spread 10.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 690    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,740    
Gross Additions 85    
Gross Reductions 280    
Ending balance 4,545 4,740  
Investment, Identifier [Axis]: ASK (Analytical Systems Keco Holdings, LLC), Warrants | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 (10)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 10  
Gross Additions 0 0  
Gross Reductions 0 10  
Ending balance $ 0 0 10
Investment, Identifier [Axis]: ATS Operating, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 5.50%    
Investment, Identifier [Axis]: ATS Operating, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 9.32%    
Spread [3],[4],[5] 5.50%    
Investment, Identifier [Axis]: ATS Operating, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.32%    
Spread [3],[4],[5] 7.50%    
Investment, Identifier [Axis]: ATS Workholding, LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 $ 0  
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [8],[9]   5.00%  
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   5.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (154)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 3,005 3,347  
Gross Additions   0  
Gross Reductions   342  
Ending balance   3,005 3,347
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[10] 5.00%    
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 5.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (620)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,088    
Gross Additions 188    
Gross Reductions 642    
Ending balance $ 634 1,088  
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[10] 5.00%    
Investment, Identifier [Axis]: ATS Workholding, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 5.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (869)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,917    
Gross Additions 0    
Gross Reductions 912    
Ending balance 1,005 1,917  
Investment, Identifier [Axis]: ATX Networks Corp., Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 3,270    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 3,270    
Gross Reductions 0    
Ending balance $ 3,270 $ 0  
Investment, Identifier [Axis]: ATX Networks Corp., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.23% [1],[5] 8.50% [2],[7]  
Spread 7.50% [1],[5] 7.50% [2],[7]  
Investment, Identifier [Axis]: ATX Networks Corp., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.23%    
Spread 7.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 134    
Amount of Interest, Fees or Dividends Credited to Income 758    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,092    
Gross Additions 362    
Gross Reductions 1,111    
Ending balance 6,343 $ 7,092  
Investment, Identifier [Axis]: ATX Networks Corp., Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   8.50%  
Spread   7.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   168  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,092 0  
Gross Additions   7,092  
Gross Reductions   0  
Ending balance   $ 7,092 0
Investment, Identifier [Axis]: ATX Networks Corp., Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   8.75%  
Spread   6.25%  
PIK Rate   1.50%  
Amount of Realized Gain/(Loss)   $ (4,528)  
Amount of Unrealized Gain/(Loss)   1,133  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 12,263  
Gross Additions   1,521  
Gross Reductions   13,784  
Ending balance   $ 0 12,263
Investment, Identifier [Axis]: ATX Networks Corp., Unsecured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.00% [1] 10.00% [2]  
PIK Rate 10.00% [1] 10.00% [2]  
Investment, Identifier [Axis]: ATX Networks Corp., Unsecured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
PIK Rate 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 306 0  
Amount of Interest, Fees or Dividends Credited to Income 329 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,963 0  
Gross Additions 635 1,963  
Gross Reductions 0 0  
Ending balance $ 2,598 $ 1,963 0
Investment, Identifier [Axis]: AVEX Aviation Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.50%  
Spread [7],[8]   6.50%  
Investment, Identifier [Axis]: AVEX Aviation Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 7.25%    
Investment, Identifier [Axis]: AVEX Aviation Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 12.17%    
Spread [3],[4],[5] 7.25%    
Investment, Identifier [Axis]: Acousti Engineering Company of Florida, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 13.23% [3],[5] 10.00% [7],[8]  
Spread 8.50% [3],[5] 8.50% [7],[8]  
Investment, Identifier [Axis]: Acousti Engineering Company of Florida, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.23% [3],[5] 14.00% [7],[8]  
Spread 8.50% [3],[5] 12.50% [7],[8]  
Investment, Identifier [Axis]: Acousti Engineering Company of Florida, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 16.17%    
Spread [3],[5] 12.50%    
Investment, Identifier [Axis]: Acumera, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 13.88%    
Spread [3],[5] 9.50%    
Investment, Identifier [Axis]: Acumera, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 13.57%    
Spread [3],[5] 9.00%    
Investment, Identifier [Axis]: Adams Publishing Group, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[11] 10.00%    
Spread [3],[5],[11] 6.00%    
Investment, Identifier [Axis]: Adams Publishing Group, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[11] 10.00%    
Spread [3],[5],[11] 7.50%    
Investment, Identifier [Axis]: American Health Staffing Group, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.00%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: American Health Staffing Group, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.00%    
Investment, Identifier [Axis]: American Health Staffing Group, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.12%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: American Nuts, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   9.00%  
Spread [7],[8]   8.00%  
Investment, Identifier [Axis]: American Nuts, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.46%    
Spread [3],[4],[5] 6.75%    
Investment, Identifier [Axis]: American Nuts, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 12.46%    
Spread [3],[4],[5] 8.75%    
Investment, Identifier [Axis]: American Teleconferencing Services, Ltd., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 7.50% [1],[10] 7.50% [2],[7],[9],[12]  
Spread 6.50% [1],[10] 6.50% [2],[7],[9],[12]  
Investment, Identifier [Axis]: American Teleconferencing Services, Ltd., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 7.50% [1],[5],[10] 7.50% [2],[7],[9]  
Spread 6.50% [1],[5],[10] 6.50% [2],[7],[9]  
Investment, Identifier [Axis]: Amounts related to investments transferred to or from other 1940 Act classification during the period | Control investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 0  
Gross Additions   0  
Gross Reductions   0  
Ending balance   0 0
Investment, Identifier [Axis]: Amounts related to investments transferred to or from other 1940 Act classification during the period | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   (694)  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   (11)  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 (12,263)  
Gross Additions   0  
Gross Reductions   0  
Ending balance   $ 0 (12,263)
Investment, Identifier [Axis]: Analytical Systems Keco Holdings, LLC, Preferred Member Units 1      
Schedule of Investments [Line Items]      
Total Rate 14.13%    
Investment, Identifier [Axis]: Analytical Systems Keco Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   10.00%  
Investment, Identifier [Axis]: Analytical Systems Keco Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 10.00%    
Investment, Identifier [Axis]: Analytical Systems Keco Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 14.13%    
Spread [5] 10.00%    
Investment, Identifier [Axis]: ArborWorks, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: ArborWorks, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 13.41%    
Spread [3],[5] 9.00%    
Investment, Identifier [Axis]: ArborWorks, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 13.56%    
Spread [3],[5] 9.00%    
Investment, Identifier [Axis]: Archer Systems, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.50%    
Investment, Identifier [Axis]: Archer Systems, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.92%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Arrow International, Inc, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.36% [3],[4],[5],[13] 9.18% [7],[8],[14]  
Spread 6.60% [3],[4],[5],[13] 7.93% [7],[8],[14]  
Investment, Identifier [Axis]: BBB Tank Services, LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 (280)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 280  
Gross Additions 0 0  
Gross Reductions 0 280  
Ending balance $ 0 $ 0 280
Investment, Identifier [Axis]: BBB Tank Services, LLC, Preferred Stock (non-voting)      
Schedule of Investments [Line Items]      
Total Rate 15.00% 15.00% [15]  
PIK Rate [15]   15.00%  
Investment, Identifier [Axis]: BBB Tank Services, LLC, Preferred Stock (non-voting) | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 15.00%    
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 (162)  
Amount of Interest, Fees or Dividends Credited to Income 0 11  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 151  
Gross Additions 0 11  
Gross Reductions 0 162  
Ending balance 0 $ 0 151
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[12]   12.00%  
Spread [7],[12]   11.00%  
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (2,242)  
Amount of Interest, Fees or Dividends Credited to Income   612  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 2,507 4,722  
Gross Additions   27  
Gross Reductions   2,242  
Ending balance   2,507 4,722
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [5],[16] 15.12%    
Spread [5],[16] 11.00%    
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 15.12%    
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 105    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 800    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 800 800  
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5],[16] 15.12%    
Spread [5],[16] 11.00%    
Investment, Identifier [Axis]: BBB Tank Services, LLC, Unsecured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 15.12%    
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 379    
Amount of Interest, Fees or Dividends Credited to Income 527    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,707    
Gross Additions 379    
Gross Reductions 0    
Ending balance 2,086 1,707  
Investment, Identifier [Axis]: Barfly Ventures, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,390 346  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,930 1,584  
Gross Additions 1,390 346  
Gross Reductions 0 0  
Ending balance $ 3,320 $ 1,930 1,584
Investment, Identifier [Axis]: Barfly Ventures, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 7.00% [3] 7.00% [8]  
Investment, Identifier [Axis]: Barfly Ventures, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 7.00% 7.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 51 49  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 710 343  
Gross Additions 1 367  
Gross Reductions 0 0  
Ending balance 711 710 343
Investment, Identifier [Axis]: Batjer TopCo, LLC, Preferred Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 631    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 4,095    
Gross Reductions 0    
Ending balance 4,095 0  
Investment, Identifier [Axis]: Batjer TopCo, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 5    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 451    
Gross Reductions 459    
Ending balance (8) 0  
Investment, Identifier [Axis]: Batjer TopCo, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Batjer TopCo, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 11.00%    
Investment, Identifier [Axis]: Batjer TopCo, LLC, Secured Debt 3 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,139    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 10,933    
Gross Reductions 0    
Ending balance $ 10,933 $ 0  
Investment, Identifier [Axis]: Berry Aviation, Inc., Preferred Member Units 1      
Schedule of Investments [Line Items]      
Total Rate 8.00% [3],[17],[18] 16.00% [8],[15],[19]  
PIK Rate 8.00% [3],[17],[18] 16.00% [8],[15],[19]  
Investment, Identifier [Axis]: Berry Aviation, Inc., Preferred Member Units 2      
Schedule of Investments [Line Items]      
Total Rate [8],[19]   8.00%  
PIK Rate 16.00% [3],[6],[17],[18] 8.00% [8],[19]  
Investment, Identifier [Axis]: Berry Aviation, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% [3] 12.00% [8]  
Spread [3] 10.50%    
PIK Rate 1.50% [3] 1.50% [8]  
Investment, Identifier [Axis]: Bettercloud, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 1.00%    
PIK Rate [3],[4],[5],[6] 6.00%    
Investment, Identifier [Axis]: Bettercloud, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.40%    
Spread [3],[4],[5] 1.00%    
PIK Rate [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: Binswanger Enterprises, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   9.50%  
Spread [7],[8]   8.50%  
Investment, Identifier [Axis]: Bluestem Brands, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   10.00%  
Spread [2],[7]   8.50%  
Investment, Identifier [Axis]: Bluestem Brands, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [1],[5],[6] 8.50%    
Investment, Identifier [Axis]: Bluestem Brands, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [1],[5] 12.94%    
Spread [1],[5] 8.50%    
Investment, Identifier [Axis]: Boccella Precast Products LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (1,860) (1,210)  
Amount of Interest, Fees or Dividends Credited to Income 66 398  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,830 6,040  
Gross Additions 0 0  
Gross Reductions 1,860 1,210  
Ending balance $ 2,970 $ 4,830 6,040
Investment, Identifier [Axis]: Boccella Precast Products LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
Investment, Identifier [Axis]: Boccella Precast Products LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 32 9  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 320 0  
Gross Additions 0 320  
Gross Reductions 0 0  
Ending balance 320 $ 320 0
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Class A Preferred Member Units      
Schedule of Investments [Line Items]      
Total Rate [15]   14.00%  
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Class A Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 2,466 1,427  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,194 10,194  
Gross Additions 0 0  
Gross Reductions 10,194 0  
Ending balance $ 0 $ 10,194 10,194
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Class B Preferred Member Units      
Schedule of Investments [Line Items]      
Total Rate 8.00% [17] 8.00% [15]  
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Class B Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 8.00%    
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 8,250 9,170  
Amount of Interest, Fees or Dividends Credited to Income 1,210 3,100  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 23,170 14,000  
Gross Additions 8,250 9,170  
Gross Reductions 0 0  
Ending balance $ 31,420 $ 23,170 14,000
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.39% [4],[5],[20] 10.50% [7]  
Spread 9.26% [4],[5],[20] 9.00% [7]  
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   10.50%  
Spread   9.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   313  
Amount of Interest, Fees or Dividends Credited to Income   3,686  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 39,000 27,225  
Gross Additions   12,275  
Gross Reductions   500  
Ending balance   39,000 27,225
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 23    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Bolder Panther Group, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.39%    
Spread 9.26%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 305    
Amount of Interest, Fees or Dividends Credited to Income 9,164    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 39,000    
Gross Additions 60,194    
Gross Reductions 0    
Ending balance 99,194 39,000  
Investment, Identifier [Axis]: Bond-Coat, Inc., Common Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   (2,320)  
Amount of Unrealized Gain/(Loss)   4,310  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 2,040  
Gross Additions   4,310  
Gross Reductions   6,350  
Ending balance   $ 0 2,040
Investment, Identifier [Axis]: Brainworks Software, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8],[9],[12]   12.50%  
Spread [7],[8],[9],[12]   9.25%  
Investment, Identifier [Axis]: Brainworks Software, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[10],[16] 12.50%    
Spread [3],[5],[10],[16] 9.25%    
Investment, Identifier [Axis]: Brainworks Software, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[10],[16] 12.50%    
Spread [3],[5],[10],[16] 9.25%    
Investment, Identifier [Axis]: Brewer Crane Holdings, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (630) 1,860  
Amount of Interest, Fees or Dividends Credited to Income 828 927  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,710 5,850  
Gross Additions 0 1,860  
Gross Reductions 630 0  
Ending balance $ 7,080 $ 7,710 5,850
Investment, Identifier [Axis]: Brewer Crane Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 14.12% [5] 11.00% [7]  
Spread 10.00% [5] 10.00% [7]  
Investment, Identifier [Axis]: Brewer Crane Holdings, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 14.12% 11.00%  
Spread 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 862 940  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,037 8,513  
Gross Additions 23 20  
Gross Reductions 2,096 496  
Ending balance 5,964 8,037 8,513
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 100    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,000    
Gross Additions 0    
Gross Reductions 0    
Ending balance 1,000 $ 1,000  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Preferred Member Units 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   1,705  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,813 9,401  
Gross Additions   412  
Gross Reductions   0  
Ending balance   9,813 9,401
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Preferred Member Units 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   100  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,000 1,000  
Gross Additions   0  
Gross Reductions   0  
Ending balance   $ 1,000 1,000
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,162    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,813    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 8,813 $ 8,813  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.00% [18] 13.00% [19]  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 132    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,000    
Gross Additions 0    
Gross Reductions 0    
Ending balance 1,000 $ 1,000  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Warrants | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   840  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,060 3,220  
Gross Additions   840  
Gross Reductions   0  
Ending balance   4,060 3,220
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Warrants 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 117    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,712    
Gross Additions 116    
Gross Reductions 0    
Ending balance 1,828 1,712  
Investment, Identifier [Axis]: Bridge Capital Solutions Corporation, Warrants 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 163    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,348    
Gross Additions 164    
Gross Reductions 0    
Ending balance 2,512 2,348  
Investment, Identifier [Axis]: Brightwood Capital Fund Investments - Fund V, LP Interests (Brightwood Capital Fund V, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,000 0  
Gross Additions   1,000  
Gross Reductions   0  
Ending balance   $ 1,000 0
Investment, Identifier [Axis]: Buca C, LLC, Preferred Member Units      
Schedule of Investments [Line Items]      
Total Rate 6.00% 6.00%  
PIK Rate 6.00% 6.00%  
Investment, Identifier [Axis]: Buca C, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 6.00%    
PIK Rate 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Buca C, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.00% 10.25% [7],[12]  
Spread [7],[12]   9.25%  
Investment, Identifier [Axis]: Buca C, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 9.00% 10.25%  
Spread   9.25%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 103 (373)  
Amount of Interest, Fees or Dividends Credited to Income 1,894 1,782  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,370 14,256  
Gross Additions 103 487  
Gross Reductions 2,136 373  
Ending balance $ 12,337 $ 14,370 14,256
Investment, Identifier [Axis]: Burning Glass Intermediate Holding Company, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   6.00%  
Spread 5.00% [3],[5],[6] 5.00% [7],[8]  
Investment, Identifier [Axis]: Burning Glass Intermediate Holding Company, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 8.91% [3],[5] 6.00% [7],[8]  
Spread 5.00% [3],[5] 5.00% [7],[8]  
Investment, Identifier [Axis]: CAI Software LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 10,252  
Amount of Unrealized Gain/(Loss)   (5,095)  
Amount of Interest, Fees or Dividends Credited to Income   2,380  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 7,190  
Gross Additions   0  
Gross Reductions   7,190  
Ending balance   $ 0 7,190
Investment, Identifier [Axis]: CAI Software LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (340)  
Amount of Interest, Fees or Dividends Credited to Income   7,570  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 47,474  
Gross Additions   23,940  
Gross Reductions   71,414  
Ending balance   0 47,474
Investment, Identifier [Axis]: CBT Nuggets, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (1,620) 4,540  
Amount of Interest, Fees or Dividends Credited to Income 3,305 2,308  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 50,620 46,080  
Gross Additions 0 4,540  
Gross Reductions 1,618 0  
Ending balance 49,002 50,620 46,080
Investment, Identifier [Axis]: CMS Minerals Investments, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 230 691  
Amount of Interest, Fees or Dividends Credited to Income 198 50  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,974 1,624  
Gross Additions 230 691  
Gross Reductions 534 341  
Ending balance $ 1,670 $ 1,974 1,624
Investment, Identifier [Axis]: Cadence Aerospace LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.99% [3],[5],[21] 9.28% [8],[22]  
Spread [3],[5],[21] 8.50%    
PIK Rate 0.01% [3],[5],[21] 0.22% [8],[22]  
Investment, Identifier [Axis]: Café Brazil, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (360) 540  
Amount of Interest, Fees or Dividends Credited to Income 178 1,012  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,570 2,030  
Gross Additions 0 540  
Gross Reductions 360 0  
Ending balance 2,210 2,570 2,030
Investment, Identifier [Axis]: California Splendor Holdings LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   7,034  
Amount of Interest, Fees or Dividends Credited to Income   1,505  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 22,785 14,496  
Gross Additions   8,289  
Gross Reductions   0  
Ending balance   $ 22,785 14,496
Investment, Identifier [Axis]: California Splendor Holdings LLC, Preferred Member Units 1      
Schedule of Investments [Line Items]      
Total Rate [15]   15.00%  
PIK Rate [15]   15.00%  
Investment, Identifier [Axis]: California Splendor Holdings LLC, Preferred Member Units 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 12,220    
Amount of Interest, Fees or Dividends Credited to Income 250    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,275    
Gross Additions 12,220    
Gross Reductions 0    
Ending balance $ 25,495 $ 13,275  
Investment, Identifier [Axis]: California Splendor Holdings LLC, Preferred Member Units 2      
Schedule of Investments [Line Items]      
Total Rate [17] 15.00%    
PIK Rate [17] 15.00%    
Investment, Identifier [Axis]: California Splendor Holdings LLC, Preferred Member Units 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 15.00%    
PIK Rate 15.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 933    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,510    
Gross Additions 933    
Gross Reductions 6,449    
Ending balance $ 3,994 $ 9,510  
Investment, Identifier [Axis]: California Splendor Holdings LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.75% [5] 11.00% [7]  
Spread 10.00% [5] 10.00% [7]  
Investment, Identifier [Axis]: California Splendor Holdings LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.75% 11.00%  
Spread 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 49 36  
Amount of Interest, Fees or Dividends Credited to Income 3,454 3,381  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 27,915 35,833  
Gross Additions 85 211  
Gross Reductions 0 8,129  
Ending balance $ 28,000 $ 27,915 35,833
Investment, Identifier [Axis]: Camin Cargo Control, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.88% [1],[5] 7.50% [2],[7]  
Spread 6.50% [1],[5] 6.50% [2],[7]  
Investment, Identifier [Axis]: Career Team Holdings, LLC, Class A Common Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 4,500 0  
Gross Additions   4,500  
Gross Reductions   0  
Ending balance   4,500 0
Investment, Identifier [Axis]: Career Team Holdings, LLC, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,500    
Gross Additions 0    
Gross Reductions 0    
Ending balance 4,500 $ 4,500  
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.50%  
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   513  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 20,050 0  
Gross Additions   20,050  
Gross Reductions   0  
Ending balance   20,050 0
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 6.00%    
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Spread 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 10    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 621    
Gross Reductions 630    
Ending balance $ (9) 0  
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.50%    
Investment, Identifier [Axis]: Career Team Holdings, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 2,607    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,050    
Gross Additions 40    
Gross Reductions 0    
Ending balance $ 20,090 20,050  
Investment, Identifier [Axis]: CaseWorthy, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.00%    
Investment, Identifier [Axis]: CaseWorthy, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.73%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: CaseWorthy, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.48%    
Spread [3],[5] 5.75%    
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 0  
Amount of Unrealized Gain/(Loss) 2,578 (320)  
Amount of Interest, Fees or Dividends Credited to Income 120 120  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,840 6,160  
Gross Additions 2,860 0  
Gross Reductions 0 320  
Ending balance 8,700 $ 5,840 6,160
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   10.00%  
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   10.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (507)  
Amount of Interest, Fees or Dividends Credited to Income   1,266  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 8,864 11,549  
Gross Additions   33  
Gross Reductions   2,718  
Ending balance   8,864 11,549
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 9.00%    
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 28    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,440    
Gross Reductions 1,440    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 13.13%    
Spread [5] 9.00%    
Investment, Identifier [Axis]: Centre Technologies Holdings, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 13.13%    
Spread 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 507    
Amount of Interest, Fees or Dividends Credited to Income 1,767    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,864    
Gross Additions 6,476    
Gross Reductions 386    
Ending balance 14,954 8,864  
Investment, Identifier [Axis]: Chamberlin Holding LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (3,660)  
Amount of Interest, Fees or Dividends Credited to Income   3,922  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 25,680 29,340  
Gross Additions   270  
Gross Reductions   3,930  
Ending balance   25,680 29,340
Investment, Identifier [Axis]: Chamberlin Holding LLC, Member Units 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (1,220)    
Amount of Interest, Fees or Dividends Credited to Income 1,853    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 24,140    
Gross Additions 0    
Gross Reductions 1,220    
Ending balance 22,920 24,140  
Investment, Identifier [Axis]: Chamberlin Holding LLC, Member Units 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 719    
Amount of Interest, Fees or Dividends Credited to Income 78    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,540    
Gross Additions 1,170    
Gross Reductions 0    
Ending balance 2,710 $ 1,540  
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   9.00%  
Spread [7]   8.00%  
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   9.00%  
Spread   8.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   2  
Amount of Interest, Fees or Dividends Credited to Income   1,544  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 17,817 15,212  
Gross Additions   4,001  
Gross Reductions   1,396  
Ending balance   17,817 15,212
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 6.00%    
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 8    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 12.13%    
Spread [5] 8.00%    
Investment, Identifier [Axis]: Chamberlin Holding LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.13%    
Spread 8.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (68)    
Amount of Interest, Fees or Dividends Credited to Income 1,845    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 17,817    
Gross Additions 68    
Gross Reductions 940    
Ending balance 16,945 17,817  
Investment, Identifier [Axis]: Chandler Signs Holdings, LLC, Class A Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,330 (1,000)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 460 1,460  
Gross Additions 1,330 0  
Gross Reductions 0 1,000  
Ending balance $ 1,790 460 1,460
Investment, Identifier [Axis]: Channel Partners Intermediateco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[23] 10.72%    
Spread [3],[4],[5],[23] 6.25%    
Investment, Identifier [Axis]: Channel Partners Intermediateco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[24] 10.71%    
Spread [3],[4],[5],[24] 6.25%    
Investment, Identifier [Axis]: Charlotte Russe, Inc, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   (3,141)  
Amount of Unrealized Gain/(Loss)   3,141  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 0  
Gross Additions   3,141  
Gross Reductions   3,141  
Ending balance   0 0
Investment, Identifier [Axis]: Charps, LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (650) 1,907  
Amount of Interest, Fees or Dividends Credited to Income 764 4,839  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,990 10,520  
Gross Additions 0 3,470  
Gross Reductions 650 0  
Ending balance 13,340 $ 13,990 10,520
Investment, Identifier [Axis]: Charps, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   15.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   4  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 669  
Gross Additions   0  
Gross Reductions   669  
Ending balance   $ 0 669
Investment, Identifier [Axis]: Charps, LLC, Unsecured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
Investment, Identifier [Axis]: Charps, LLC, Unsecured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (44) 260  
Amount of Interest, Fees or Dividends Credited to Income 613 1,007  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,694 8,475  
Gross Additions 44 559  
Gross Reductions 44 3,340  
Ending balance 5,694 $ 5,694 8,475
Investment, Identifier [Axis]: Chisholm Energy Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.75%  
Spread [7],[8]   6.25%  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   1,640  
Amount of Interest, Fees or Dividends Credited to Income   2,391  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,780 9,140  
Gross Additions   1,640  
Gross Reductions   0  
Ending balance   10,780 9,140
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Member Units 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (2,030)    
Amount of Interest, Fees or Dividends Credited to Income 758    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,250    
Gross Additions 0    
Gross Reductions 2,030    
Ending balance 8,220 10,250  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Member Units 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 80    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 530    
Gross Additions 80    
Gross Reductions 0    
Ending balance $ 610 530  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 9.00%    
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt - SF 9.00% | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 4    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [7]   10.50%  
Spread 9.00% [4],[5],[6] 9.50% [7]  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.23% 10.00%  
Spread 9.00%    
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   110  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,071 1,100  
Gross Additions   0  
Gross Reductions   29  
Ending balance   1,071 1,100
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 1 - 13.23% | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,255    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,401    
Gross Additions 39    
Gross Reductions 0    
Ending balance $ 10,440 $ 10,401  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.23% [4],[5] 10.00%  
Spread [4],[5] 9.00%    
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.50%  
Spread   9.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   1,167  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 10,401 10,853  
Gross Additions   (52)  
Gross Reductions   400  
Ending balance   10,401 10,853
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 2 - 10.00% | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 107    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,071    
Gross Additions 1    
Gross Reductions 33    
Ending balance $ 1,039 $ 1,071  
Investment, Identifier [Axis]: Clad-Rex Steel, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 10.00%    
Investment, Identifier [Axis]: Clarius BIGS, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 15.00% [3],[10],[16] 15.00% [8],[9],[12]  
PIK Rate 15.00% [3],[10],[16] 15.00% [8],[9],[12]  
Investment, Identifier [Axis]: Classic H&G Holdings, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 9,380 5,750  
Amount of Interest, Fees or Dividends Credited to Income 1,711 1,070  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 15,260 9,510  
Gross Additions 9,377 5,750  
Gross Reductions 0 0  
Ending balance $ 24,637 $ 15,260 9,510
Investment, Identifier [Axis]: Classic H&G Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 9.75% [5] 7.00% [7]  
Spread 6.00% [5] 6.00% [7]  
Investment, Identifier [Axis]: Classic H&G Holdings, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 9.75% 7.00%  
Spread 6.00% 6.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 639 83  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,000 0  
Gross Additions 11,720 4,000  
Gross Reductions 11,160 0  
Ending balance $ 4,560 $ 4,000 0
Investment, Identifier [Axis]: Classic H&G Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Investment, Identifier [Axis]: Classic H&G Holdings, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (43) (82)  
Amount of Interest, Fees or Dividends Credited to Income 1,606 2,210  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 19,274 24,800  
Gross Additions 43 82  
Gross Reductions 43 5,608  
Ending balance 19,274 19,274 24,800
Investment, Identifier [Axis]: Cody Pools, Inc., Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 10,540 32,700  
Amount of Interest, Fees or Dividends Credited to Income 4,015 3,100  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 47,640 14,940  
Gross Additions 10,540 32,700  
Gross Reductions 0 0  
Ending balance 58,180 $ 47,640 14,940
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.25%  
Spread [7]   10.50%  
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.25%  
Spread   10.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   242  
Amount of Interest, Fees or Dividends Credited to Income   2,357  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 42,484 14,216  
Gross Additions   32,737  
Gross Reductions   4,469  
Ending balance   42,484 14,216
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [5] 15.38%    
Spread [5] 10.50%    
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 15.38%    
Spread 10.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 19    
Amount of Interest, Fees or Dividends Credited to Income 119    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (13)    
Gross Additions 4,971    
Gross Reductions 3,496    
Ending balance $ 1,462 (13)  
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 15.38%    
Spread [5] 10.50%    
Investment, Identifier [Axis]: Cody Pools, Inc., Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 15.38%    
Spread 10.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (86)    
Amount of Interest, Fees or Dividends Credited to Income 5,615    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 42,497    
Gross Additions 86    
Gross Reductions 1,782    
Ending balance 40,801 42,497  
Investment, Identifier [Axis]: Colonial Electric Company LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 30 1,450  
Amount of Interest, Fees or Dividends Credited to Income 1,397 1,480  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,130 0  
Gross Additions 30 9,130  
Gross Reductions 0 0  
Ending balance 9,160 $ 9,130 0
Investment, Identifier [Axis]: Colonial Electric Company LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Investment, Identifier [Axis]: Colonial Electric Company LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   2,705  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 24,351 0  
Gross Additions   24,981  
Gross Reductions   630  
Ending balance   24,351 0
Investment, Identifier [Axis]: Colonial Electric Company LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 48    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,600    
Gross Reductions 1,600    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Colonial Electric Company LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Colonial Electric Company LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 2,953    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 24,351    
Gross Additions 60    
Gross Reductions 1,260    
Ending balance 23,151 24,351  
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 7,830 5,220  
Amount of Interest, Fees or Dividends Credited to Income 632 474  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 12,000 6,780  
Gross Additions 7,830 5,220  
Gross Reductions 0 0  
Ending balance 19,830 $ 12,000 6,780
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   10.00%  
Spread [7]   9.00%  
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   10.00%  
Spread   9.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (18)  
Amount of Interest, Fees or Dividends Credited to Income   777  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 6,477 7,954  
Gross Additions   18  
Gross Reductions   1,495  
Ending balance   6,477 7,954
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6],[16] 9.00%    
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 13.13%    
Spread [5] 9.00%    
Investment, Identifier [Axis]: CompareNetworks Topco, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.13%    
Spread 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (16)    
Amount of Interest, Fees or Dividends Credited to Income 642    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,477    
Gross Additions 16    
Gross Reductions 1,252    
Ending balance $ 5,241 $ 6,477  
Investment, Identifier [Axis]: Computer Data Source, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.50%  
Spread [7],[8]   7.50%  
Investment, Identifier [Axis]: Computer Data Source, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[25] 12.56%    
Spread [3],[5],[25] 8.00%    
Investment, Identifier [Axis]: Computer Data Source, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.56%    
Spread [3],[5] 8.00%    
Investment, Identifier [Axis]: Congruent Credit Opportunities Funds, LP Interests (Congruent Credit Opportunities Fund III, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (142)    
Amount of Interest, Fees or Dividends Credited to Income 566    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,959    
Gross Additions 0    
Gross Reductions 2,302    
Ending balance 7,657 $ 9,959  
Investment, Identifier [Axis]: Congruent Credit Opportunities Funds, LP Interests (Congruent Credit Opportunities Fund II, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   (4,449)  
Amount of Unrealized Gain/(Loss)   4,355  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 94  
Gross Additions   4,355  
Gross Reductions   4,449  
Ending balance   0 94
Investment, Identifier [Axis]: Congruent Credit Opportunities Funds, LP Interests (Congruent Credit Opportunities Fund III, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (96)  
Amount of Interest, Fees or Dividends Credited to Income   776  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,959 11,540  
Gross Additions   0  
Gross Reductions   1,581  
Ending balance   9,959 11,540
Investment, Identifier [Axis]: Copper Trail Energy Fund I, LP - CTMH, LP Interests (CTMH, LP) | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 710 747  
Gross Additions 0 0  
Gross Reductions 122 37  
Ending balance 588 710 747
Investment, Identifier [Axis]: Copper Trail Energy Fund I, LP, LP Interests (Copper Trail Energy Fund I, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   (203)  
Amount of Unrealized Gain/(Loss)   379  
Amount of Interest, Fees or Dividends Credited to Income   378  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 1,782  
Gross Additions   379  
Gross Reductions   2,161  
Ending balance   0 1,782
Investment, Identifier [Axis]: DMA Industries, LLC, Preferred Equity | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,316 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,944 0  
Gross Additions 1,316 5,944  
Gross Reductions 0 0  
Ending balance $ 7,260 $ 5,944 0
Investment, Identifier [Axis]: DMA Industries, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: DMA Industries, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 165 0  
Amount of Interest, Fees or Dividends Credited to Income 2,621 521  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,993 0  
Gross Additions 207 20,993  
Gross Reductions 0 0  
Ending balance $ 21,200 $ 20,993 0
Investment, Identifier [Axis]: DTE Enterprises, LLC, Class A Preferred Member Units      
Schedule of Investments [Line Items]      
Total Rate 8.00% [3] 8.00% [8]  
PIK Rate 8.00% [3] 8.00% [8]  
Investment, Identifier [Axis]: DTE Enterprises, LLC, Class AA Preferred Member Units (non-voting)      
Schedule of Investments [Line Items]      
Total Rate 10.00% [3],[17] 10.00% [7],[8]  
PIK Rate 10.00% [3],[17] 10.00% [7],[8]  
Investment, Identifier [Axis]: DTE Enterprises, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   9.50%  
Spread [7],[8]   8.00%  
Investment, Identifier [Axis]: DTE Enterprises, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 7.50%    
Investment, Identifier [Axis]: DTE Enterprises, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.24%    
Spread [3],[5] 7.50%    
Investment, Identifier [Axis]: Dalton US Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.90%    
Spread [3],[4],[5] 8.00%    
Investment, Identifier [Axis]: Dalton US Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 8.00%    
Investment, Identifier [Axis]: Dalton US Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 12.56%    
Spread [3],[4],[5] 8.00%    
Investment, Identifier [Axis]: Darr Equipment LP, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [8]   12.50%  
PIK Rate [8]   1.00%  
Investment, Identifier [Axis]: Datacom, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ (7,324)  
Amount of Unrealized Gain/(Loss) 60 7,324  
Amount of Interest, Fees or Dividends Credited to Income 96 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,610 0  
Gross Additions 60 9,934  
Gross Reductions 0 7,324  
Ending balance $ 2,670 $ 2,610 0
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   5.00%  
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 7.50%    
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 7.50% 5.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (628)  
Amount of Interest, Fees or Dividends Credited to Income   793  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 7,668 0  
Gross Additions   8,404  
Gross Reductions   736  
Ending balance   7,668 0
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 1 - 7.50% | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 4    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 223    
Gross Reductions 0    
Ending balance $ 223 $ 0  
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 7.50%    
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 7.50% 8.00%  
Amount of Realized Gain/(Loss)   $ (3,601)  
Amount of Unrealized Gain/(Loss)   2,130  
Amount of Interest, Fees or Dividends Credited to Income   1  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 12,146  
Gross Additions   2,130  
Gross Reductions   14,276  
Ending balance   0 12,146
Investment, Identifier [Axis]: Datacom, LLC, Secured Debt 2 - 7.50% | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 228    
Amount of Interest, Fees or Dividends Credited to Income 829    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,668    
Gross Additions 391    
Gross Reductions 270    
Ending balance 7,789 7,668  
Investment, Identifier [Axis]: Digital Products Holdings LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 200 200  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,835 9,835  
Gross Additions 0 0  
Gross Reductions 0 0  
Ending balance $ 9,835 $ 9,835 9,835
Investment, Identifier [Axis]: Digital Products Holdings LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 14.13% [5] 11.00% [7]  
Spread 10.00% [5] 10.00% [7]  
Investment, Identifier [Axis]: Digital Products Holdings LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 14.13% 11.00%  
Spread 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 1,991 1,978  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 16,801 18,077  
Gross Additions 43 44  
Gross Reductions 1,321 1,320  
Ending balance 15,523 16,801 18,077
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Preferred Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 3,870 (1,030)  
Amount of Interest, Fees or Dividends Credited to Income 1,371 672  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 18,350 19,380  
Gross Additions 3,870 0  
Gross Reductions 0 1,030  
Ending balance 22,220 $ 18,350 19,380
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   11.00%  
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   137  
Amount of Interest, Fees or Dividends Credited to Income   2,034  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 24,048 15,006  
Gross Additions   9,512  
Gross Reductions   470  
Ending balance   24,048 15,006
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 11.00%    
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 88    
Amount of Interest, Fees or Dividends Credited to Income 235    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (22)    
Gross Additions 4,272    
Gross Reductions 4,250    
Ending balance $ 0 (22)  
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 15.13%    
Spread [5] 11.00%    
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 15.13%    
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 145    
Amount of Interest, Fees or Dividends Credited to Income 327    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 27,267    
Gross Reductions 0    
Ending balance $ 27,267 0  
Investment, Identifier [Axis]: Direct Marketing Solutions, Inc., Secured Debt 3 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (137)    
Amount of Interest, Fees or Dividends Credited to Income 2,953    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 24,070    
Gross Additions 0    
Gross Reductions 24,070    
Ending balance 0 24,070  
Investment, Identifier [Axis]: Dos Rios Partners, LP Interests (Dos Rios Partners - A, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 64 715  
Amount of Unrealized Gain/(Loss) (335) 1,560  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,280 1,720  
Gross Additions 64 1,560  
Gross Reductions 446 0  
Ending balance 2,898 3,280 1,720
Investment, Identifier [Axis]: Dos Rios Partners, LP Interests (Dos Rios Partners, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 202 2,252  
Amount of Unrealized Gain/(Loss) (1,055) 4,912  
Amount of Interest, Fees or Dividends Credited to Income 1 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,329 5,417  
Gross Additions 202 4,912  
Gross Reductions 1,404 0  
Ending balance 9,127 10,329 5,417
Investment, Identifier [Axis]: Dos Rios Stone Products LLC, Class A Preferred Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 690 (610)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 640 1,250  
Gross Additions 690 0  
Gross Reductions 0 610  
Ending balance $ 1,330 $ 640 1,250
Investment, Identifier [Axis]: Dynamic Communities, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   9.50%  
Spread [7],[8]   8.50%  
Investment, Identifier [Axis]: Dynamic Communities, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 9.18%    
Spread [3],[4],[5] 4.50%    
PIK Rate [3],[4],[5] 9.18%    
Investment, Identifier [Axis]: Dynamic Communities, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.18%    
Spread [3],[4],[5] 6.50%    
PIK Rate [3],[4],[5] 11.18%    
Investment, Identifier [Axis]: EIG Fund Investments, LP Interests (EIG Global Private Debt Fund-A, L.P.) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 20 $ 9  
Amount of Unrealized Gain/(Loss) 0 166  
Amount of Interest, Fees or Dividends Credited to Income 103 53  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 547 526  
Gross Additions 1,102 200  
Gross Reductions 636 179  
Ending balance 1,013 $ 547 526
Investment, Identifier [Axis]: EPIC Y-Grade Services, LP, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   7.00%  
Spread [2],[7]   6.00%  
Investment, Identifier [Axis]: East Teak Fine Hardwoods, Inc., Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ (80)  
Amount of Unrealized Gain/(Loss)   180  
Amount of Interest, Fees or Dividends Credited to Income   100  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 300  
Gross Additions   180  
Gross Reductions   480  
Ending balance   $ 0 300
Investment, Identifier [Axis]: Eastern Wholesale Fence LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: Eastern Wholesale Fence LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.73%    
Spread [3],[5] 7.00%    
Investment, Identifier [Axis]: Eastern Wholesale Fence LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.73%    
Spread [3],[5] 7.00%    
Investment, Identifier [Axis]: Eastern Wholesale Fence LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.73%    
Spread [3],[5] 7.00%    
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Common Stock 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 9,668    
Gross Reductions 2,065    
Ending balance 7,603 $ 0  
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Common Stock 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,558    
Gross Reductions 0    
Ending balance $ 1,558 0  
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [4],[5],[6] 6.00%    
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 2    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 9    
Ending balance $ (9) 0  
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 948    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 18,594    
Gross Reductions 0    
Ending balance $ 18,594 0  
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 9.00%    
Investment, Identifier [Axis]: Elgin AcquireCo, LLC, Secured Debt 3 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 144    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 6,301    
Gross Reductions 7    
Ending balance $ 6,294 $ 0  
Investment, Identifier [Axis]: Emerald Technologies Acquisition Co, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [1],[4],[5] 10.67%    
Spread [1],[4],[5] 6.25%    
Investment, Identifier [Axis]: Engineering Research & Consulting, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.68%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Engineering Research & Consulting, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.92%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Event Holdco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8],[19]   8.00%  
Spread [7],[8],[19]   7.00%  
Investment, Identifier [Axis]: Event Holdco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[18] 10.67%    
Spread [3],[5],[18] 7.00%    
Investment, Identifier [Axis]: Event Holdco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[18] 10.67%    
Spread [3],[5],[18] 7.00%    
Investment, Identifier [Axis]: Flame King Holdings, LLC, Preferred Equity | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 7,180 0  
Amount of Interest, Fees or Dividends Credited to Income 2,153 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,400 0  
Gross Additions 7,180 10,400  
Gross Reductions 0 0  
Ending balance $ 17,580 $ 10,400 0
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 10.75% [5] 7.50% [7]  
Spread 6.50% [5] 6.50% [7]  
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   884  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 20,996 0  
Gross Additions   20,996  
Gross Reductions   0  
Ending balance   20,996 0
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 1 - 10.75% | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.75%    
Spread 6.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 60    
Amount of Interest, Fees or Dividends Credited to Income 669    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,324    
Gross Additions 1,276    
Gross Reductions 0    
Ending balance $ 7,600 $ 6,324  
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.25% [5] 12.00% [7]  
Spread 9.00% [5] 11.00% [7]  
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   7.50%  
Spread   6.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   77  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 6,324 0  
Gross Additions   6,324  
Gross Reductions   0  
Ending balance   6,324 0
Investment, Identifier [Axis]: Flame King Holdings, LLC, Secured Debt 2 - 15.25% | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.25%    
Spread 9.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 162    
Amount of Interest, Fees or Dividends Credited to Income 2,739    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,996    
Gross Additions 204    
Gross Reductions 0    
Ending balance $ 21,200 $ 20,996  
Investment, Identifier [Axis]: Flip Electronics LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8],[26]   9.09%  
Spread [7],[8],[26]   8.09%  
Investment, Identifier [Axis]: Flip Electronics LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.21%    
Spread [3],[4],[5] 7.50%    
Investment, Identifier [Axis]: Flip Electronics LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 12.19%    
Spread [3],[4],[5] 7.50%    
Investment, Identifier [Axis]: Fortna Acquisition Co., Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [8]   5.09%  
Spread [8]   5.00%  
Investment, Identifier [Axis]: Freeport Financial SBIC Fund LP, LP Interests (Freeport Financial SBIC Fund LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (128) 814  
Amount of Interest, Fees or Dividends Credited to Income 3 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,078 5,264  
Gross Additions 0 814  
Gross Reductions 2,595 0  
Ending balance 3,483 6,078 5,264
Investment, Identifier [Axis]: Freeport Financial SBIC Fund LP, LP Interests (Freeport First Lien Loan Fund III LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (57) 66  
Amount of Interest, Fees or Dividends Credited to Income 442 751  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,231 10,321  
Gross Additions 0 66  
Gross Reductions 1,383 3,156  
Ending balance $ 5,848 $ 7,231 10,321
Investment, Identifier [Axis]: Fuse, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% [1] 12.00% [2]  
Investment, Identifier [Axis]: GFG Group, LLC., Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 150 2,090  
Amount of Interest, Fees or Dividends Credited to Income 577 629  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,990 0  
Gross Additions 150 6,990  
Gross Reductions 0 0  
Ending balance $ 7,140 $ 6,990 0
Investment, Identifier [Axis]: GFG Group, LLC., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.00% 12.00%  
Investment, Identifier [Axis]: GFG Group, LLC., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 9.00% 12.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (34) 110  
Amount of Interest, Fees or Dividends Credited to Income 1,248 1,601  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 12,545 0  
Gross Additions 34 15,745  
Gross Reductions 1,234 3,200  
Ending balance 11,345 12,545 0
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (1,750) 1,290  
Amount of Interest, Fees or Dividends Credited to Income 2,525 4,264  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 46,190 44,900  
Gross Additions 0 1,290  
Gross Reductions 1,750 0  
Ending balance 44,440 $ 46,190 44,900
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   8.10%  
Spread   8.00%  
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   8.10%  
Spread   8.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   213  
Amount of Interest, Fees or Dividends Credited to Income   1,786  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 38,885 16,775  
Gross Additions   22,110  
Gross Reductions   0  
Ending balance   38,885 16,775
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 10.12%    
Spread 6.00%    
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 10.12%    
Spread 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 25    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 670    
Gross Reductions 0    
Ending balance $ 670 0  
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.12%    
Spread 8.00%    
Investment, Identifier [Axis]: GRT Rubber Technologies LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.12%    
Spread 8.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (33)    
Amount of Interest, Fees or Dividends Credited to Income 3,973    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 38,885    
Gross Additions 1,641    
Gross Reductions 33    
Ending balance $ 40,493 $ 38,885  
Investment, Identifier [Axis]: GS HVAM Intermediate, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   6.75%  
Spread [7],[8]   5.75%  
Investment, Identifier [Axis]: GS HVAM Intermediate, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.20%    
Spread [3],[5] 6.50%    
Investment, Identifier [Axis]: GS HVAM Intermediate, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.24%    
Spread [3],[5] 6.50%    
Investment, Identifier [Axis]: GS Operating, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   6.50%  
Investment, Identifier [Axis]: GULF PACIFIC ACQUISITION, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.42%    
Spread [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: GULF PACIFIC ACQUISITION, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.00%    
Investment, Identifier [Axis]: GULF PACIFIC ACQUISITION, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.73%    
Spread [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 1,190 (5,638)  
Amount of Interest, Fees or Dividends Credited to Income 895 3,921  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 49,700 52,490  
Gross Additions 1,190 2,848  
Gross Reductions 0 5,638  
Ending balance 50,890 $ 49,700 52,490
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   9.50%  
Spread [7]   7.50%  
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   9.50%  
Spread   7.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   32  
Amount of Interest, Fees or Dividends Credited to Income   2,019  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 21,598 19,838  
Gross Additions   1,761  
Gross Reductions   1  
Ending balance   21,598 19,838
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [4],[5],[6] 8.50%    
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 8.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 6    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [4],[5] 11.50%    
Spread [4],[5] 8.50%    
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 11.50%    
Spread 8.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 393    
Amount of Interest, Fees or Dividends Credited to Income 1,152    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 64,078    
Gross Reductions 0    
Ending balance $ 64,078 0  
Investment, Identifier [Axis]: Gamber-Johnson Holdings, LLC, Secured Debt 3 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 7.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (63)    
Amount of Interest, Fees or Dividends Credited to Income 2,233    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 21,598    
Gross Additions 0    
Gross Reductions 21,598    
Ending balance 0 21,598  
Investment, Identifier [Axis]: Garreco, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (470) 860  
Amount of Interest, Fees or Dividends Credited to Income 240 300  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,270 1,410  
Gross Additions 0 860  
Gross Reductions 470 0  
Ending balance $ 1,800 $ 2,270 1,410
Investment, Identifier [Axis]: Garreco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.50% [5],[27] 9.00% [7],[28]  
Spread 8.00% [5],[27] 8.00% [7],[28]  
Investment, Identifier [Axis]: Garreco, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 9.50% 9.00%  
Spread 8.00% 8.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 383 405  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,196 4,519  
Gross Additions 0 0  
Gross Reductions 370 323  
Ending balance $ 3,826 $ 4,196 4,519
Investment, Identifier [Axis]: GeoStabilization International (GSI), Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.44% [1] 5.35% [2]  
Spread 5.25% [1] 5.25% [2]  
Investment, Identifier [Axis]: GoWireless Holdings, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   7.50%  
Spread [2],[7]   6.50%  
Investment, Identifier [Axis]: Grupo Hima San Pablo, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [2],[7],[9],[12]   9.25%  
Spread [2],[7],[9],[12]   7.00%  
Investment, Identifier [Axis]: Grupo Hima San Pablo, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [2],[9],[12]   13.75%  
Investment, Identifier [Axis]: Grupo Hima San Pablo, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [2],[12]   12.00%  
Investment, Identifier [Axis]: Gulf Manufacturing, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 1,150 1,130  
Amount of Interest, Fees or Dividends Credited to Income 1,715 2,109  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,640 4,510  
Gross Additions 1,150 1,130  
Gross Reductions 0 0  
Ending balance 6,790 5,640 4,510
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 0  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Preferred Equity | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (1,820)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 5,600    
Gross Reductions 1,820    
Ending balance $ 3,780 $ 0  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [7],[12]   10.50%  
Spread 9.50% [5],[6] 9.50% [7],[12]  
PIK Rate [7],[12]   5.25%  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 9.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 7    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 257    
Gross Additions 0    
Gross Reductions 257    
Ending balance 0 $ 257  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   10.50%  
Spread   9.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   21  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 257 250  
Gross Additions   14  
Gross Reductions   7  
Ending balance   $ 257 250
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50% [12]  
PIK Rate [12]   6.25%  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
PIK Rate 6.25%    
Amount of Realized Gain/(Loss) $ (5,822)    
Amount of Unrealized Gain/(Loss) 3,848    
Amount of Interest, Fees or Dividends Credited to Income 503    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 9,717    
Gross Additions 0    
Gross Reductions 9,717    
Ending balance 0 $ 9,717  
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.50%  
PIK Rate   6.25%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (2,757)  
Amount of Interest, Fees or Dividends Credited to Income   1,282  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 9,717 12,044  
Gross Additions   849  
Gross Reductions   3,176  
Ending balance   9,717 12,044
Investment, Identifier [Axis]: Gulf Publishing Holdings, LLC, Secured Debt 3 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (116)    
Amount of Interest, Fees or Dividends Credited to Income 77    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 2,400    
Gross Reductions 116    
Ending balance $ 2,284 $ 0  
Investment, Identifier [Axis]: HDC/HW Intermediate Holdings, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.50%  
Spread [7],[8]   7.50%  
Investment, Identifier [Axis]: HDC/HW Intermediate Holdings, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 14.34%    
Spread [3],[4],[5] 9.50%    
PIK Rate [3],[4],[5] 2.00%    
Investment, Identifier [Axis]: HDC/HW Intermediate Holdings, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 14.34%    
Spread [3],[4],[5] 9.50%    
PIK Rate [3],[4],[5] 2.00%    
Investment, Identifier [Axis]: HEADLANDS OP-CO LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.50%    
Investment, Identifier [Axis]: HEADLANDS OP-CO LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.50%    
Investment, Identifier [Axis]: HEADLANDS OP-CO LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.62%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: HOWLCO LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.69% [1],[5],[29],[30] 7.00% [2],[7],[31],[32]  
Spread 6.00% [1],[5],[29],[30] 6.00% [2],[7],[31],[32]  
Investment, Identifier [Axis]: HPEP 3, L.P., LP Interests (423 COR, LP) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,400    
Gross Reductions 0    
Ending balance 1,400 $ 0  
Investment, Identifier [Axis]: HPEP 3, L.P., LP Interests (HPEP 3, L.P.) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 779 0  
Amount of Unrealized Gain/(Loss) 254 1,332  
Amount of Interest, Fees or Dividends Credited to Income (48) 177  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,712 3,258  
Gross Additions 1,033 1,706  
Gross Reductions 1,414 252  
Ending balance 4,331 4,712 3,258
Investment, Identifier [Axis]: HPEP 3, L.P., LP Interests (HPEP 4, L.P.) | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 2,332    
Gross Reductions 0    
Ending balance 2,332 0  
Investment, Identifier [Axis]: Harrison Hydra-Gen, Ltd., Common Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (250) (1,920)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,530 5,450  
Gross Additions 0 0  
Gross Reductions 250 1,920  
Ending balance 3,280 3,530 5,450
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   7,000  
Amount of Interest, Fees or Dividends Credited to Income   1,914  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 15,450 8,450  
Gross Additions   7,000  
Gross Reductions   0  
Ending balance   15,450 8,450
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Preferred Member Units 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 2,780    
Amount of Interest, Fees or Dividends Credited to Income 803    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,680    
Gross Additions 2,780    
Gross Reductions 0    
Ending balance 17,460 14,680  
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Preferred Member Units 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 150    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 770    
Gross Additions 150    
Gross Reductions 0    
Ending balance $ 920 $ 770  
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 10.13% [5] 7.00% [7],[31]  
Spread 6.00% [5] 6.00% [7],[31]  
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.13% 7.00%  
Spread 6.00% 6.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 3 0  
Amount of Interest, Fees or Dividends Credited to Income 230 70  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,585 0  
Gross Additions 600 2,585  
Gross Reductions 0 0  
Ending balance $ 3,185 $ 2,585 0
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 9.00% 8.00% [31]  
Investment, Identifier [Axis]: Hawk Ridge Systems, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 9.00% 8.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (13) 94  
Amount of Interest, Fees or Dividends Credited to Income 3,054 2,023  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 34,800 18,400  
Gross Additions 3,013 16,400  
Gross Reductions 13 0  
Ending balance $ 37,800 $ 34,800 18,400
Investment, Identifier [Axis]: Heartland Dental, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.88%    
Spread [3],[5] 6.50%    
Investment, Identifier [Axis]: Heartland Dental, LLC, Secured Debt September 09,2020      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.50%  
Spread [7],[8]   6.50%  
Investment, Identifier [Axis]: Houston Plating and Coatings, LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (810) (1,870)  
Amount of Interest, Fees or Dividends Credited to Income 17 261  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,210 5,080  
Gross Additions 0 0  
Gross Reductions 810 1,870  
Ending balance $ 2,400 $ 3,210 5,080
Investment, Identifier [Axis]: Houston Plating and Coatings, LLC, Unsecured Convertible Debt      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Investment, Identifier [Axis]: Houston Plating and Coatings, LLC, Unsecured Convertible Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 40 60  
Amount of Interest, Fees or Dividends Credited to Income 243 243  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,960 2,900  
Gross Additions 40 60  
Gross Reductions 0 0  
Ending balance $ 3,000 $ 2,960 2,900
Investment, Identifier [Axis]: Hybrid Promotions, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.07% [3],[4] 9.25% [7],[8]  
Spread 8.25% [3],[4] 8.25% [7],[8]  
Investment, Identifier [Axis]: I-45 SLF LLC, Member Units (Fully diluted 20.0%; 21.75% profits interest) | Affiliate investments      
Schedule of Investments [Line Items]      
Diluted, percentage 20.00%    
Profits, percentage 21.75%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (2,629)    
Amount of Interest, Fees or Dividends Credited to Income 2,028    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,387    
Gross Additions 0    
Gross Reductions 2,629    
Ending balance 11,758 $ 14,387  
Investment, Identifier [Axis]: I-45 SLF LLC, Member Units (Fully diluted 20.0%; 24.40% profits interest)      
Schedule of Investments [Line Items]      
Diluted, percentage [31],[33]   20.00%  
Profits, percentage [31],[33]   24.40%  
Investment, Identifier [Axis]: I-45 SLF LLC, Member Units (Fully diluted 20.0%; 24.40% profits interest) | Affiliate investments      
Schedule of Investments [Line Items]      
Diluted, percentage   20.00%  
Profits, percentage   24.40%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (202)  
Amount of Interest, Fees or Dividends Credited to Income   1,861  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 14,387 15,789  
Gross Additions   800  
Gross Reductions   2,202  
Ending balance   $ 14,387 15,789
Investment, Identifier [Axis]: IG Parent Corporation, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   6.75%  
Spread [2],[7]   5.75%  
Investment, Identifier [Axis]: IG Parent Corporation, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [1],[4],[5],[34] 10.17%    
Spread [1],[4],[5],[34] 5.75%    
Investment, Identifier [Axis]: IG Parent Corporation, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [1],[4],[5] 10.17%    
Spread [1],[4],[5] 5.75%    
Investment, Identifier [Axis]: INW Manufacturing, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.48% [1],[5] 6.50% [2],[7]  
Spread 5.75% [1],[5] 5.75% [2],[7]  
Investment, Identifier [Axis]: Implus Footcare, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.98% [3],[5] 8.75% [7],[8]  
Spread 7.75% [3],[5] 7.75% [7],[8]  
PIK Rate [3],[5] 1.50%    
Investment, Identifier [Axis]: Independent Pet Partners Intermediate Holdings, LLC, Preferred Stock (non-voting) 1      
Schedule of Investments [Line Items]      
Total Rate 6.00% [3] 6.00% [8]  
PIK Rate 6.00% [3] 6.00% [8]  
Investment, Identifier [Axis]: Independent Pet Partners Intermediate Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 13.00% [3],[5],[35] 7.20% [8],[36]  
Spread [3],[5],[35] 5.50%    
PIK Rate [3],[5],[35] 13.00%    
Investment, Identifier [Axis]: Independent Pet Partners Intermediate Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 6.00% [3],[10] 6.00% [8]  
PIK Rate 6.00% [3],[10] 6.00% [8]  
Investment, Identifier [Axis]: Independent Pet Partners Intermediate Holdings, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4] 14.42%    
Spread [3],[4] 10.00%    
PIK Rate [3],[4] 14.42%    
Investment, Identifier [Axis]: Industrial Services Acquisition, LLC, Preferred Member Units 1      
Schedule of Investments [Line Items]      
Total Rate 10.00% [3],[17],[18] 10.00% [8],[15],[19]  
PIK Rate 10.00% [3],[17],[18] 10.00% [8],[15],[19]  
Investment, Identifier [Axis]: Industrial Services Acquisition, LLC, Preferred Member Units 2      
Schedule of Investments [Line Items]      
Total Rate 20.00% [3],[17],[18] 20.00% [8],[15],[19]  
PIK Rate 20.00% [3],[17],[18] 20.00% [8],[15],[19]  
Investment, Identifier [Axis]: Industrial Services Acquisition, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.75%  
Spread [7],[8]   6.75%  
Investment, Identifier [Axis]: Industrial Services Acquisition, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.50%    
Spread [3],[5] 6.75%    
Investment, Identifier [Axis]: Industrial Services Acquisition, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.50%    
Spread [3],[5] 6.75%    
Investment, Identifier [Axis]: Infolinks Media Buyco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.00%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: Infolinks Media Buyco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 5.50%    
Investment, Identifier [Axis]: Infolinks Media Buyco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.23%    
Spread [3],[5] 5.50%    
Investment, Identifier [Axis]: Interface Security Systems, L.L.C, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 14.22% [3],[37] 11.75% [7],[8]  
Spread 10.00% [3],[37] 10.00% [7],[8]  
Investment, Identifier [Axis]: Interface Security Systems, L.L.C, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.07% [3],[5],[10] 9.75% [7],[8],[9]  
Spread 7.00% [3],[5],[10] 7.00% [7],[8],[9]  
PIK Rate 1.00% [3],[5],[10] 1.00% [7],[8],[9]  
Investment, Identifier [Axis]: Intermedia Holdings, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.38% [1],[5] 7.00% [2],[7]  
Spread 6.00% [1],[5] 6.00% [2],[7]  
Investment, Identifier [Axis]: Investments transferred from other 1940 Act classification during the period | Control investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 3,677    
Amount of Interest, Fees or Dividends Credited to Income 1,491    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,123    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 $ 6,123  
Investment, Identifier [Axis]: Investments transferred from other 1940 Act classification during the period | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (3,538)    
Amount of Interest, Fees or Dividends Credited to Income (1,491)    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (15,962)    
Gross Additions 10,853    
Gross Reductions 10,853    
Ending balance $ 0 $ (15,962)  
Investment, Identifier [Axis]: Invincible Boat Company, LLC., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   6.50%  
Investment, Identifier [Axis]: Invincible Boat Company, LLC., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.14%    
Spread [3],[5] 6.50%    
Investment, Identifier [Axis]: Invincible Boat Company, LLC., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.17%    
Spread [3],[5] 6.50%    
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,798 0  
Gross Additions 0 1,798  
Gross Reductions 0 0  
Ending balance $ 1,798 $ 1,798 0
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 12.50% 13.00%  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 591    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,557    
Gross Additions 10    
Gross Reductions 67    
Ending balance 4,500 $ 4,557  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 1 - 12.50% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   201  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 3,170 0  
Gross Additions   3,170  
Gross Reductions   0  
Ending balance   $ 3,170 0
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
PIK Rate   12.50%  
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 411    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,170    
Gross Additions 7    
Gross Reductions 47    
Ending balance 3,130 $ 3,170  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 2 - 12.50% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   408  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 8,944 0  
Gross Additions   9,088  
Gross Reductions   144  
Ending balance   $ 8,944 0
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 3 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,134    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,944    
Gross Additions 0    
Gross Reductions 0    
Ending balance 8,944 $ 8,944  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 3 - 12.50% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   731  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 19,805 0  
Gross Additions   19,805  
Gross Reductions   0  
Ending balance   $ 19,805 0
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 4      
Schedule of Investments [Line Items]      
Total Rate 12.50% 12.50%  
PIK Rate   12.50%  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 4 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.50% 13.00%  
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 2,572    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 19,805    
Gross Additions 42    
Gross Reductions 288    
Ending balance 19,559 $ 19,805  
Investment, Identifier [Axis]: Iron-Main Investments, LLC, Secured Debt 4 - 13.00% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   346  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 4,557 0  
Gross Additions   4,557  
Gross Reductions   0  
Ending balance   $ 4,557 0
Investment, Identifier [Axis]: Isagenix International, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.93% [1],[5],[10] 6.75% [2],[7]  
Spread 7.75% [1],[5],[10] 5.75% [2],[7]  
Investment, Identifier [Axis]: J&J Services, Inc., Preferred Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 10,952  
Amount of Unrealized Gain/(Loss)   (5,595)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 12,680  
Gross Additions   0  
Gross Reductions   12,680  
Ending balance   $ 0 12,680
Investment, Identifier [Axis]: J&J Services, Inc., Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   11.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (103)  
Amount of Interest, Fees or Dividends Credited to Income   1,264  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 12,800  
Gross Additions   103  
Gross Reductions   12,903  
Ending balance   $ 0 12,800
Investment, Identifier [Axis]: JTI Electrical & Mechanical, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.00%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: JTI Electrical & Mechanical, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.00%    
Investment, Identifier [Axis]: JTI Electrical & Mechanical, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.73%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: Jackmont Hospitality, Inc., Preferred Equity      
Schedule of Investments [Line Items]      
Total Rate [3],[17] 12.00%    
PIK Rate [3],[17] 12.00%    
Investment, Identifier [Axis]: Jackmont Hospitality, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: Jackmont Hospitality, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.23%    
Spread [3],[5] 7.50%    
Investment, Identifier [Axis]: Jackmont Hospitality, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.23%    
Spread [3],[5] 7.50%    
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 2,550 4,800  
Amount of Interest, Fees or Dividends Credited to Income 2,784 1,937  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 12,420 7,620  
Gross Additions 2,550 4,800  
Gross Reductions 0 0  
Ending balance $ 14,970 $ 12,420 7,620
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   10.00%  
Spread [7]   6.75%  
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [6] 6.75%    
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   10.00%  
Spread   6.75%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (13)  
Amount of Interest, Fees or Dividends Credited to Income   313  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 2,550 3,400  
Gross Additions   13  
Gross Reductions   863  
Ending balance   2,550 3,400
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 1 - 6.75% | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 6.75%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 3    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 13.75%    
Spread [5] 6.75%    
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   10.00%  
Spread   6.75%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   3  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 0  
Gross Additions   0  
Gross Reductions   0  
Ending balance   0 0
Investment, Identifier [Axis]: Jensen Jewelers of Idaho, LLC, Secured Debt 2 - 13.75% | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.75%    
Spread 6.75%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (8)    
Amount of Interest, Fees or Dividends Credited to Income 292    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,550    
Gross Additions 8    
Gross Reductions 108    
Ending balance $ 2,450 $ 2,550  
Investment, Identifier [Axis]: Joerns Healthcare, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 18.00% [1] 7.00% [2],[7]  
Spread [2],[7]   6.00%  
Investment, Identifier [Axis]: Joerns Healthcare, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 19.75% [1],[10] 15.00% [2]  
PIK Rate 19.75% [1],[10] 15.00% [2]  
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Preferred Equity | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 2,390 0  
Amount of Interest, Fees or Dividends Credited to Income 1,062 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,150 0  
Gross Additions 2,390 3,150  
Gross Reductions 0 0  
Ending balance 5,540 $ 3,150 0
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   13.00%  
Spread [7]   11.50%  
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Spread   11.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   208  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 11,344 0  
Gross Additions   11,344  
Gross Reductions   0  
Ending balance   11,344 0
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 11.50%    
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 11.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 14    
Amount of Interest, Fees or Dividends Credited to Income 13    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (18)    
Gross Additions 18    
Gross Reductions 0    
Ending balance $ 0 (18)  
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 15.63%    
Spread [5] 11.50%    
Investment, Identifier [Axis]: Johnson Downie Opco, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 15.63%    
Spread 11.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 79    
Amount of Interest, Fees or Dividends Credited to Income 1,503    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,362    
Gross Additions 114    
Gross Reductions 1,477    
Ending balance 9,999 11,362  
Investment, Identifier [Axis]: JorVet Holdings, LLC, Preferred Equity | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 922    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 10,741    
Gross Reductions 0    
Ending balance $ 10,741 0  
Investment, Identifier [Axis]: JorVet Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: JorVet Holdings, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 2,680    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 25,432    
Gross Reductions 0    
Ending balance 25,432 0  
Investment, Identifier [Axis]: KBK Industries, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,950 420  
Amount of Interest, Fees or Dividends Credited to Income 1,671 992  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,620 13,200  
Gross Additions 1,950 420  
Gross Reductions 0 0  
Ending balance $ 15,570 $ 13,620 13,200
Investment, Identifier [Axis]: KMS, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.25%  
Spread [7],[8]   7.25%  
Investment, Identifier [Axis]: KMS, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.00%    
Spread [3],[5] 7.25%    
Investment, Identifier [Axis]: KMS, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 12.00%    
Spread [3],[5] 7.25%    
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Member Units 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 390    
Amount of Interest, Fees or Dividends Credited to Income 113    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,460    
Gross Additions 390    
Gross Reductions 0    
Ending balance 2,850 $ 2,460  
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Member Units 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   1,370  
Amount of Interest, Fees or Dividends Credited to Income   92  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,770 13,400  
Gross Additions   1,370  
Gross Reductions   0  
Ending balance   14,770 13,400
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Preferred Equity | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (5,090)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 12,310    
Gross Additions 0    
Gross Reductions 5,090    
Ending balance $ 7,220 $ 12,310  
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 11.50% 11.50%  
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 11.50% 11.50%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 2,430 2,526  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,324 22,269  
Gross Additions 50 55  
Gross Reductions 0 2,000  
Ending balance $ 20,374 $ 20,324 22,269
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 9.00% 9.00%  
Investment, Identifier [Axis]: Kickhaefer Manufacturing Company, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 9.00% 9.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 352 354  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,876 3,909  
Gross Additions 2 0  
Gross Reductions 36 33  
Ending balance $ 3,842 $ 3,876 3,909
Investment, Identifier [Axis]: Klein Hersh, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.75%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: Kore Wireless Group Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.08% [1],[4] 5.72% [2],[31]  
Spread 5.50% [1],[4] 5.50% [2],[31]  
Investment, Identifier [Axis]: L.F. Manufacturing Holdings, LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 617 $ 0  
Amount of Unrealized Gain/(Loss) (541) 510  
Amount of Interest, Fees or Dividends Credited to Income 224 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,560 2,050  
Gross Additions 617 510  
Gross Reductions 3,177 0  
Ending balance $ 0 $ 2,560 2,050
Investment, Identifier [Axis]: L.F. Manufacturing Holdings, LLC, Preferred Member Units (non-voting)      
Schedule of Investments [Line Items]      
Total Rate [8],[15]   14.00%  
PIK Rate [8],[15]   14.00%  
Investment, Identifier [Axis]: L.F. Manufacturing Holdings, LLC, Preferred Member Units (non-voting) | Affiliate investments      
Schedule of Investments [Line Items]      
PIK Rate 14.00%    
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 9 14  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 107 93  
Gross Additions 10 14  
Gross Reductions 117 0  
Ending balance $ 0 $ 107 93
Investment, Identifier [Axis]: LL Management, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.25%  
Spread [7],[8]   7.25%  
Investment, Identifier [Axis]: LL Management, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.21%    
Spread [3],[4],[5] 7.25%    
Investment, Identifier [Axis]: LL Management, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.67%    
Spread [3],[4],[5] 7.25%    
Investment, Identifier [Axis]: LL Management, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.67%    
Spread [3],[4],[5] 7.25%    
Investment, Identifier [Axis]: LLFlex, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.74% [3],[5] 10.00% [7],[8]  
Spread 9.00% [3],[5] 9.00% [7],[8]  
Investment, Identifier [Axis]: LaserAway Intermediate Holdings II, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   6.50%  
Spread [2],[7]   5.75%  
Investment, Identifier [Axis]: Lightbox Holdings, L.P., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.73% [1] 5.22% [2]  
Spread 5.00% [1] 5.00% [2]  
Investment, Identifier [Axis]: Logix Acquisition Company, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.13% [3],[5] 6.75% [7],[8]  
Spread 5.75% [3],[5] 5.75% [7],[8]  
Investment, Identifier [Axis]: MB2 Dental Solutions, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   7.00%  
Spread [2],[7]   6.00%  
Investment, Identifier [Axis]: MB2 Dental Solutions, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [1],[4],[5] 10.42%    
Spread [1],[4],[5] 6.00%    
Investment, Identifier [Axis]: MB2 Dental Solutions, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [1],[4],[5] 10.42%    
Spread [1],[4],[5] 6.00%    
Investment, Identifier [Axis]: MH Corbin Holding LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (2,370)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 2,370  
Gross Additions   0  
Gross Reductions   2,370  
Ending balance   0 2,370
Investment, Identifier [Axis]: MH Corbin Holding LLC, Preferred Member Units 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 0  
Investment, Identifier [Axis]: MH Corbin Holding LLC, Preferred Member Units 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: MH Corbin Holding LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Investment, Identifier [Axis]: MH Corbin Holding LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 699 (2,059)  
Amount of Interest, Fees or Dividends Credited to Income 999 1,137  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,934 8,280  
Gross Additions 708 34  
Gross Reductions 2,094 2,380  
Ending balance 4,548 $ 5,934 8,280
Investment, Identifier [Axis]: MS Private Loan Fund I, LP, Unsecured Debt      
Schedule of Investments [Line Items]      
Total Rate [31],[33]   5.00%  
Investment, Identifier [Axis]: MS Private Loan Fund, LP Interests | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 $ 0  
Amount of Unrealized Gain/(Loss) 502 81  
Amount of Interest, Fees or Dividends Credited to Income 742 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,581 0  
Gross Additions 12,252 2,581  
Gross Reductions 0 0  
Ending balance 14,833 2,581 0
Investment, Identifier [Axis]: MS Private Loan Fund, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 28    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 5,300    
Gross Reductions 5,300    
Ending balance 0 0  
Investment, Identifier [Axis]: MS Private Loan Fund, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 431    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 63,151    
Gross Additions 13,700    
Gross Reductions 76,851    
Ending balance 0 $ 63,151  
Investment, Identifier [Axis]: MS Private Loan Fund, Unsecured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   5.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   1,402  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 63,151 0  
Gross Additions   66,726  
Gross Reductions   3,575  
Ending balance   63,151 0
Investment, Identifier [Axis]: MSC Adviser I, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (17,470) 23,638  
Amount of Interest, Fees or Dividends Credited to Income 9,297 6,216  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 140,400 116,760  
Gross Additions 0 23,640  
Gross Reductions 17,470 0  
Ending balance 122,930 $ 140,400 116,760
Investment, Identifier [Axis]: MSC Income Fund Inc., Unsecured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   5.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   2,179  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 0  
Gross Additions   60,000  
Gross Reductions   60,000  
Ending balance   0 0
Investment, Identifier [Axis]: MSC Income Fund, Inc., Common Equity | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 3    
Amount of Interest, Fees or Dividends Credited to Income 30    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 753    
Gross Reductions 0    
Ending balance $ 753 $ 0  
Investment, Identifier [Axis]: Mac Lean-Fogg Company, Preferred Stock      
Schedule of Investments [Line Items]      
Total Rate [8]   13.75%  
PIK Rate [8]   9.25%  
Investment, Identifier [Axis]: Mac Lean-Fogg Company, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   5.88%  
Spread [7],[8]   5.25%  
Investment, Identifier [Axis]: Mako Steel, LP, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.25%  
Investment, Identifier [Axis]: Mako Steel, LP, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[38] 11.79%    
Spread [3],[5],[38] 7.25%    
Investment, Identifier [Axis]: Mako Steel, LP, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.09%    
Spread [3],[5] 7.25%    
Investment, Identifier [Axis]: Market Force Information, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Market Force Information, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 15.13% [5] 12.00% [7]  
Spread 11.00% [5] 11.00% [7]  
Investment, Identifier [Axis]: Market Force Information, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 15.13% 12.00%  
Spread 11.00% 11.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (163) 0  
Amount of Interest, Fees or Dividends Credited to Income 592 387  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,400 1,600  
Gross Additions 2,853 1,800  
Gross Reductions 163 0  
Ending balance $ 6,090 $ 3,400 1,600
Investment, Identifier [Axis]: Market Force Information, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10] 12.00% [12]  
PIK Rate 12.00% [10] 12.00% [12]  
Investment, Identifier [Axis]: Market Force Information, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
PIK Rate 12.00% 12.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (7,325) (4,626)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,936 13,562  
Gross Additions 0 0  
Gross Reductions 7,326 4,626  
Ending balance 1,610 8,936 13,562
Investment, Identifier [Axis]: Meisler Operating LLC, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   17,048  
Amount of Unrealized Gain/(Loss)   (7,413)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 16,010  
Gross Additions   (550)  
Gross Reductions   15,460  
Ending balance   0 16,010
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Common Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,537    
Gross Reductions 0    
Ending balance $ 1,537 0  
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Preferred Equity      
Schedule of Investments [Line Items]      
Total Rate [17] 8.00%    
PIK Rate [17] 8.00%    
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Preferred Equity | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 8.00%    
PIK Rate 8.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 95    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 6,010    
Gross Reductions 0    
Ending balance 6,010 0  
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 16    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.75%    
Investment, Identifier [Axis]: MetalForming AcquireCo, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.75%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,143    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 23,576    
Gross Reductions 0    
Ending balance $ 23,576 $ 0  
Investment, Identifier [Axis]: Microbe Formulas, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.25%    
Investment, Identifier [Axis]: Microbe Formulas, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 9.86%    
Spread [3],[4],[5] 6.25%    
Investment, Identifier [Axis]: Mills Fleet Farm Group, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.66% [3],[5] 7.25% [7],[8]  
Spread 6.25% [3],[5] 6.25% [7],[8]  
Investment, Identifier [Axis]: MonitorUS Holding, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[29],[30] 11.73%    
Spread [3],[5],[29],[30] 7.00%    
Investment, Identifier [Axis]: MonitorUS Holding, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6],[29],[30] 7.00%    
Investment, Identifier [Axis]: MonitorUS Holding, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5],[29],[30] 11.73%    
Spread [3],[5],[29],[30] 7.00%    
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Common Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 13,990 (150)  
Amount of Interest, Fees or Dividends Credited to Income 4,202 1,271  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,840 8,990  
Gross Additions 13,990 0  
Gross Reductions 0 150  
Ending balance 22,830 $ 8,840 8,990
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   1  
Amount of Interest, Fees or Dividends Credited to Income   820  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,378 6,723  
Gross Additions   10  
Gross Reductions   355  
Ending balance   6,378 6,723
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 4    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 10.00%    
Investment, Identifier [Axis]: Mystic Logistics Holdings, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 10.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (1)    
Amount of Interest, Fees or Dividends Credited to Income 607    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,378    
Gross Additions 1    
Gross Reductions 633    
Ending balance 5,746 6,378  
Investment, Identifier [Axis]: NAPCO Precast, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (1,730) (2,540)  
Amount of Interest, Fees or Dividends Credited to Income 4 1,553  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,560 16,100  
Gross Additions 0 0  
Gross Reductions 1,730 2,540  
Ending balance $ 11,830 $ 13,560 16,100
Investment, Identifier [Axis]: NBG Acquisition Inc, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.67% [1],[5] 6.50% [7]  
Spread 5.50% [1],[5] 5.50% [7]  
Investment, Identifier [Axis]: NGL Transportation & Storage, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [1],[5] 10.70%    
Spread [1],[5] 6.00%    
Investment, Identifier [Axis]: NNE Partners, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [8]   9.37%  
Spread [8]   4.75%  
PIK Rate [8]   4.50%  
Investment, Identifier [Axis]: NRI Clinical Research, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 8,787  
Amount of Unrealized Gain/(Loss)   (4,835)  
Amount of Interest, Fees or Dividends Credited to Income   2,805  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 5,600  
Gross Additions   (749)  
Gross Reductions   4,851  
Ending balance   $ 0 5,600
Investment, Identifier [Axis]: NRI Clinical Research, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   9.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (48)  
Amount of Interest, Fees or Dividends Credited to Income   380  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 5,620  
Gross Additions   48  
Gross Reductions   5,668  
Ending balance   0 5,620
Investment, Identifier [Axis]: NRI Clinical Research, LLC, Warrants | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (1,238)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 1,490  
Gross Additions   0  
Gross Reductions   1,490  
Ending balance   0 1,490
Investment, Identifier [Axis]: NRP Jones, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   3,619  
Amount of Interest, Fees or Dividends Credited to Income   (45)  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,440 2,821  
Gross Additions   3,619  
Gross Reductions   0  
Ending balance   6,440 2,821
Investment, Identifier [Axis]: NRP Jones, LLC, Member Units 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (1,585)    
Amount of Interest, Fees or Dividends Credited to Income 578    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,200    
Gross Additions 0    
Gross Reductions 1,585    
Ending balance 4,615 6,200  
Investment, Identifier [Axis]: NRP Jones, LLC, Member Units 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (65)    
Amount of Interest, Fees or Dividends Credited to Income 17    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 240    
Gross Additions 0    
Gross Reductions 65    
Ending balance $ 175 $ 240  
Investment, Identifier [Axis]: NRP Jones, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: NRP Jones, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 253 253  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,080 2,080  
Gross Additions 0 0  
Gross Reductions 0 0  
Ending balance $ 2,080 $ 2,080 2,080
Investment, Identifier [Axis]: NTM Acquisition Corp., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.50% [1],[5] 8.25% [2],[7]  
Spread 6.25% [1],[5] 6.25% [2],[7]  
PIK Rate 1.00% [1],[5] 1.00% [2],[7]  
Investment, Identifier [Axis]: NWN Corporation, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.50%  
Spread [7],[8]   6.50%  
Investment, Identifier [Axis]: NWN Corporation, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[39] 10.85%    
Spread [3],[4],[5],[39] 8.00%    
Investment, Identifier [Axis]: NWN Corporation, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 12.56%    
Spread [3],[4],[5] 8.00%    
Investment, Identifier [Axis]: NWN Corporation, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3] 20.00%    
PIK Rate [3] 20.00%    
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC (NVS), Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 713  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,700 6,500  
Gross Additions 0 1,200  
Gross Reductions 0 0  
Ending balance 7,700 $ 7,700 6,500
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC (NVS), Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   1,466  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 15,241 10,395  
Gross Additions   4,846  
Gross Reductions   0  
Ending balance   15,241 10,395
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC (NVS), Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 7.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 10    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC (NVS), Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 122    
Amount of Interest, Fees or Dividends Credited to Income 1,778    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,829    
Gross Additions 15,265    
Gross Reductions 0    
Ending balance $ 20,094 4,829  
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC (NVS), Secured Debt 3 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 66    
Amount of Interest, Fees or Dividends Credited to Income 1,299    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,412    
Gross Additions 88    
Gross Reductions 0    
Ending balance $ 10,500 $ 10,412  
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread [5],[6] 7.00%    
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: Nebraska Vet AcquireCo, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: NexRev LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (2,913) 1,220  
Amount of Interest, Fees or Dividends Credited to Income 81 80  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,690 1,470  
Gross Additions 1,333 1,220  
Gross Reductions 2,913 0  
Ending balance 1,110 $ 2,690 1,470
Investment, Identifier [Axis]: NexRev LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   11.00%  
Investment, Identifier [Axis]: NexRev LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (1,839)  
Amount of Interest, Fees or Dividends Credited to Income   1,883  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,045 16,727  
Gross Additions   38  
Gross Reductions   2,720  
Ending balance   14,045 16,727
Investment, Identifier [Axis]: NexRev LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 29    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 800    
Gross Additions 0    
Gross Reductions 800    
Ending balance $ 0 800  
Investment, Identifier [Axis]: NexRev LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 11.00%    
Investment, Identifier [Axis]: NexRev LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (729)    
Amount of Interest, Fees or Dividends Credited to Income 1,923    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,245    
Gross Additions 0    
Gross Reductions 4,768    
Ending balance $ 8,477 $ 13,245  
Investment, Identifier [Axis]: NinjaTrader, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.25%  
Spread [7],[8]   6.25%  
Investment, Identifier [Axis]: NinjaTrader, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.25%    
Investment, Identifier [Axis]: NinjaTrader, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.25%    
Investment, Identifier [Axis]: NinjaTrader, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 9.99%    
Spread [3],[5] 6.25%    
Investment, Identifier [Axis]: Northstar Group Services, Inc, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   6.50%  
Spread [2],[7]   5.50%  
Investment, Identifier [Axis]: NuStep, LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   2,720  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 13,500 10,780  
Gross Additions   2,720  
Gross Reductions   0  
Ending balance   13,500 10,780
Investment, Identifier [Axis]: NuStep, LLC, Preferred Member Units 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (5,460)    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 13,500    
Gross Additions 0    
Gross Reductions 5,460    
Ending balance 8,040 13,500  
Investment, Identifier [Axis]: NuStep, LLC, Preferred Member Units 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 3,088    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 5,150    
Gross Reductions 0    
Ending balance $ 5,150 $ 0  
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 10.63% [5] 7.50% [7]  
Spread 6.50% [5] 6.50% [7]  
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   4  
Amount of Interest, Fees or Dividends Credited to Income   1,991  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 17,240 17,193  
Gross Additions   47  
Gross Reductions   0  
Ending balance   17,240 17,193
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 1 - 10.63% | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 10.63%    
Spread 6.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 323    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,720    
Gross Additions 2,679    
Gross Reductions 0    
Ending balance $ 4,399 $ 1,720  
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00% 11.00%  
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   7.50%  
Spread   6.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   58  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,720 0  
Gross Additions   2,120  
Gross Reductions   400  
Ending balance   1,720 0
Investment, Identifier [Axis]: NuStep, LLC, Secured Debt 2 - 12.00% | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (4)    
Amount of Interest, Fees or Dividends Credited to Income 2,180    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 17,240    
Gross Additions 1,178    
Gross Reductions 4    
Ending balance 18,414 17,240  
Investment, Identifier [Axis]: OMi Holdings, Inc., Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (170)  
Amount of Interest, Fees or Dividends Credited to Income   1,578  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,210 20,380  
Gross Additions   0  
Gross Reductions   170  
Ending balance   $ 20,210 20,380
Investment, Identifier [Axis]: OMi Holdings, Inc., Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   169  
Amount of Interest, Fees or Dividends Credited to Income   1,109  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 18,000 0  
Gross Additions   18,000  
Gross Reductions   0  
Ending balance   18,000 0
Investment, Identifier [Axis]: OMi Topco, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 2,600    
Amount of Interest, Fees or Dividends Credited to Income 2,154    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 20,210    
Gross Additions 2,600    
Gross Reductions 0    
Ending balance $ 22,810 $ 20,210  
Investment, Identifier [Axis]: OMi Topco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: OMi Topco, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (53)    
Amount of Interest, Fees or Dividends Credited to Income 2,135    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 18,000    
Gross Additions 53    
Gross Reductions 2,303    
Ending balance $ 15,750 $ 18,000  
Investment, Identifier [Axis]: OVG Business Services, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.64% [3],[5] 7.25% [7],[8]  
Spread 6.25% [3],[5] 6.25% [7],[8]  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 (830)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 0  
Gross Additions 0 830  
Gross Reductions 0 830  
Ending balance $ 0 $ 0 0
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Preferred Stock      
Schedule of Investments [Line Items]      
Total Rate 7.00% 7.00%  
PIK Rate 7.00% 7.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Preferred Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 7.00%    
PIK Rate 7.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 $ 0  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
PIK Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   930  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 8,229 7,299  
Gross Additions   930  
Gross Reductions   0  
Ending balance   $ 8,229 7,299
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10] 12.00%  
PIK Rate 12.00% [10] 12.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
PIK Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (395)    
Amount of Interest, Fees or Dividends Credited to Income 28    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 935    
Gross Additions 28    
Gross Reductions 394    
Ending balance $ 569 $ 935  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10] 12.00%  
PIK Rate 12.00% [10] 12.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
PIK Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (403)    
Amount of Interest, Fees or Dividends Credited to Income 29    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 954    
Gross Additions 29    
Gross Reductions 403    
Ending balance $ 580 $ 954  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10] 12.00%  
PIK Rate 12.00% [10] 12.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 3 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
PIK Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (867)    
Amount of Interest, Fees or Dividends Credited to Income 62    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,055    
Gross Additions 62    
Gross Reductions 868    
Ending balance $ 1,249 $ 2,055  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 4      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10] 12.00%  
PIK Rate 12.00% [10] 12.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Secured Debt 4 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
PIK Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (1,809)    
Amount of Interest, Fees or Dividends Credited to Income 129    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,285    
Gross Additions 129    
Gross Reductions 1,808    
Ending balance $ 2,606 $ 4,285  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Unsecured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.00% [10] 10.00%  
PIK Rate 10.00% [10] 10.00%  
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Unsecured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.00% 10.00%  
PIK Rate 10.00% 10.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 5 11  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 192 64  
Gross Additions 113 139  
Gross Reductions 0 11  
Ending balance 305 192 64
Investment, Identifier [Axis]: OnAsset Intelligence, Inc., Warrants | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 830  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 0  
Gross Additions 0 830  
Gross Reductions 0 830  
Ending balance 0 0 0
Investment, Identifier [Axis]: Oneliance, LLC, Preferred Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 2 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,056 0  
Gross Additions 0 1,056  
Gross Reductions 0 0  
Ending balance 1,056 $ 1,056 0
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   11.00%  
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   335  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 5,547 0  
Gross Additions   5,547  
Gross Reductions   0  
Ending balance   5,547 0
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 11.00%    
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 15.13%    
Spread [5] 11.00%    
Investment, Identifier [Axis]: Oneliance, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 15.13%    
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 750    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,547    
Gross Additions 12    
Gross Reductions 0    
Ending balance 5,559 5,547  
Investment, Identifier [Axis]: Orttech Holdings, LLC, Preferred Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,750 0  
Amount of Interest, Fees or Dividends Credited to Income 900 130  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,000 0  
Gross Additions 1,750 12,600  
Gross Reductions 0 2,600  
Ending balance 11,750 $ 10,000 0
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   11.00%  
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   1,522  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 24,151 0  
Gross Additions   24,151  
Gross Reductions   0  
Ending balance   24,151 0
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [5],[6] 11.00%    
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 16    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 175    
Gross Additions 0    
Gross Reductions 175    
Ending balance $ 0 175  
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 15.13%    
Spread [5] 11.00%    
Investment, Identifier [Axis]: Orttech Holdings, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 15.13%    
Spread 11.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 3,207    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 23,976    
Gross Additions 53    
Gross Reductions 600    
Ending balance $ 23,429 $ 23,976  
Investment, Identifier [Axis]: Ospemifene Royalty Sub LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.50% [3],[10] 11.50% [8],[9]  
Investment, Identifier [Axis]: Other | Control investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 0  
Gross Additions 0 0  
Gross Reductions 0 0  
Ending balance 0 0 0
Investment, Identifier [Axis]: Other | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 0  
Gross Additions 0 0  
Gross Reductions 0 0  
Ending balance 0 0 0
Investment, Identifier [Axis]: PCI Holding Company, Inc., Preferred Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (203)  
Amount of Interest, Fees or Dividends Credited to Income   2,852  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0 4,130  
Gross Additions   0  
Gross Reductions   4,130  
Ending balance   0 4,130
Investment, Identifier [Axis]: PPL RVs, Inc., Common Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   2,860  
Amount of Interest, Fees or Dividends Credited to Income   555  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,360 11,500  
Gross Additions   2,860  
Gross Reductions   0  
Ending balance   14,360 11,500
Investment, Identifier [Axis]: PPL RVs, Inc., Common Stock 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 4,590    
Amount of Interest, Fees or Dividends Credited to Income 1,627    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 14,360    
Gross Additions 4,590    
Gross Reductions 0    
Ending balance 18,950 14,360  
Investment, Identifier [Axis]: PPL RVs, Inc., Common Stock 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 238    
Gross Reductions 0    
Ending balance 238 $ 0  
Investment, Identifier [Axis]: PPL RVs, Inc., Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   7.50%  
Spread   7.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (25)  
Amount of Interest, Fees or Dividends Credited to Income   957  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 12,382 11,806  
Gross Additions   801  
Gross Reductions   225  
Ending balance   $ 12,382 11,806
Investment, Identifier [Axis]: PPL RVs, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [7]   7.50%  
Spread 7.00% [5],[6] 7.00% [7]  
Investment, Identifier [Axis]: PPL RVs, Inc., Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Spread 7.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 9    
Amount of Interest, Fees or Dividends Credited to Income 79    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 727    
Gross Additions 1,273    
Gross Reductions 2,000    
Ending balance $ 0 $ 727  
Investment, Identifier [Axis]: PPL RVs, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 10.25% [5] 7.50% [7]  
Spread 7.00% [5] 7.00% [7]  
Investment, Identifier [Axis]: PPL RVs, Inc., Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 10.25%    
Spread 7.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 247    
Amount of Interest, Fees or Dividends Credited to Income 1,714    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,655    
Gross Additions 10,000    
Gross Reductions 0    
Ending balance $ 21,655 $ 11,655  
Investment, Identifier [Axis]: PT Network, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.50%  
Spread [7],[8]   5.50%  
PIK Rate [7],[8]   2.00%  
Investment, Identifier [Axis]: PTL US Bidco, Inc, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6],[29] 7.25%    
Investment, Identifier [Axis]: PTL US Bidco, Inc, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[29] 11.80%    
Spread [3],[4],[5],[29] 7.25%    
Investment, Identifier [Axis]: Paragon Healthcare, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.26%    
Spread [3],[4],[5] 5.75%    
Investment, Identifier [Axis]: Paragon Healthcare, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[40] 9.96%    
Spread [3],[4],[5],[40] 5.75%    
Investment, Identifier [Axis]: Paragon Healthcare, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 9.81%    
Spread [3],[4],[5] 5.75%    
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 16,290 11,030  
Amount of Interest, Fees or Dividends Credited to Income 8,204 3,599  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 26,970 15,940  
Gross Additions 16,290 11,030  
Gross Reductions 0 0  
Ending balance 43,260 $ 26,970 15,940
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   236  
Amount of Interest, Fees or Dividends Credited to Income   4,259  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 32,674 37,201  
Gross Additions   311  
Gross Reductions   4,838  
Ending balance   32,674 37,201
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 31    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,500    
Gross Reductions 1,500    
Ending balance 0 0  
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 0  
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Pearl Meyer Topco LLC, Secured Debt 3 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (92)    
Amount of Interest, Fees or Dividends Credited to Income 3,714    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 32,674    
Gross Additions 92    
Gross Reductions 4,085    
Ending balance 28,681 32,674  
Investment, Identifier [Axis]: Pegasus Research Group, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   (1,550)  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,280 8,830  
Gross Additions   0  
Gross Reductions   1,550  
Ending balance   7,280 8,830
Investment, Identifier [Axis]: Principle Environmental, LLC, Common Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (120) (490)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 710 0  
Gross Additions 0 1,200  
Gross Reductions 120 490  
Ending balance 590 710 0
Investment, Identifier [Axis]: Principle Environmental, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 1,260 (449)  
Amount of Interest, Fees or Dividends Credited to Income 1,355 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,160 10,500  
Gross Additions 1,260 1,109  
Gross Reductions 0 449  
Ending balance 12,420 $ 11,160 10,500
Investment, Identifier [Axis]: Principle Environmental, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (62)  
Amount of Interest, Fees or Dividends Credited to Income   929  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,273 6,397  
Gross Additions   2,938  
Gross Reductions   2,062  
Ending balance   $ 7,273 6,397
Investment, Identifier [Axis]: Principle Environmental, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Investment, Identifier [Axis]: Principle Environmental, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 104    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,465    
Gross Additions 9    
Gross Reductions 1,474    
Ending balance $ 0 $ 1,465  
Investment, Identifier [Axis]: Principle Environmental, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.00% 13.00%  
Investment, Identifier [Axis]: Principle Environmental, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 804    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,808    
Gross Additions 24    
Gross Reductions 26    
Ending balance 5,806 $ 5,808  
Investment, Identifier [Axis]: Principle Environmental, LLC, Warrants | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   330  
Amount of Interest, Fees or Dividends Credited to Income   0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 870  
Gross Additions   330  
Gross Reductions   1,200  
Ending balance   $ 0 870
Investment, Identifier [Axis]: Project Eagle Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.75%  
Spread [7],[8]   6.75%  
Investment, Identifier [Axis]: Project Eagle Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 6.25%    
Investment, Identifier [Axis]: Project Eagle Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.64%    
Spread [3],[5] 6.25%    
Investment, Identifier [Axis]: Quality Lease Service, LLC, Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 76 (461)  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,148 4,460  
Gross Additions 77 0  
Gross Reductions 1,700 2,312  
Ending balance $ 525 $ 2,148 4,460
Investment, Identifier [Axis]: RA Outdoors LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.75%  
Spread [7],[8]   6.75%  
Investment, Identifier [Axis]: RA Outdoors LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.75%    
Investment, Identifier [Axis]: RA Outdoors LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.56%    
Spread [3],[4],[5] 6.75%    
Investment, Identifier [Axis]: RTIC Subsidiary Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   9.00%  
Spread [7],[8]   7.75%  
Investment, Identifier [Axis]: RTIC Subsidiary Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[41] 12.02%    
Spread [3],[4],[5],[41] 7.75%    
Investment, Identifier [Axis]: RTIC Subsidiary Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.49%    
Spread [3],[4],[5] 7.75%    
Investment, Identifier [Axis]: Research Now Group, Inc. and Survey Sampling International, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 8.84% [1],[5] 6.50% [2],[7]  
Spread 5.50% [1],[5] 5.50% [2],[7]  
Investment, Identifier [Axis]: River Aggregates, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 340 40  
Amount of Interest, Fees or Dividends Credited to Income 0 125  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,280 3,240  
Gross Additions 340 40  
Gross Reductions 0 0  
Ending balance 3,620 3,280 3,240
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Preferred Equity | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 3,810 0  
Amount of Interest, Fees or Dividends Credited to Income 558 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,070 0  
Gross Additions 3,810 11,070  
Gross Reductions 0 0  
Ending balance 14,880 $ 11,070 0
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7]   12.00%  
Spread [7]   11.00%  
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Spread   11.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   621  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 35,956 0  
Gross Additions   35,956  
Gross Reductions   0  
Ending balance   35,956 0
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 32    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (44)    
Gross Additions 9    
Gross Reductions 0    
Ending balance $ (35) (44)  
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [5] 12.50%    
Investment, Identifier [Axis]: Robbins Bros. Jewelry, Inc., Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 4,678    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 36,000    
Gross Additions 78    
Gross Reductions 674    
Ending balance 35,404 36,000  
Investment, Identifier [Axis]: Rocaceia, LLC (Quality Lease and Rental Holdings, LLC), Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Rocaceia, LLC (Quality Lease and Rental Holdings, LLC), Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% [10],[16],[42] 12.00% [9],[12],[43]  
Investment, Identifier [Axis]: Rocaceia, LLC (Quality Lease and Rental Holdings, LLC), Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ (86)    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Roof Opco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.00%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: Roof Opco, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.97%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Roof Opco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.32%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Roof Opco, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 10.32%    
Spread [3],[4],[5] 6.50%    
Investment, Identifier [Axis]: Rug Doctor, LLC., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.25%  
Spread [7],[8]   6.25%  
Investment, Identifier [Axis]: Rug Doctor, LLC., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 13.02%    
Spread [3],[4],[5] 6.25%    
PIK Rate [3],[4],[5] 2.00%    
Investment, Identifier [Axis]: Rug Doctor, LLC., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 13.02%    
Spread [3],[4],[5] 6.25%    
PIK Rate [3],[4],[5] 2.00%    
Investment, Identifier [Axis]: SI East, LLC (Stavig), Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 2,080 6,572  
Amount of Interest, Fees or Dividends Credited to Income 647 2,340  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,570 9,780  
Gross Additions 2,080 6,572  
Gross Reductions 0 4,782  
Ending balance 13,650 $ 11,570 9,780
Investment, Identifier [Axis]: SI East, LLC (Stavig), Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   10.25%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   (90)  
Amount of Interest, Fees or Dividends Credited to Income   4,032  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 65,850 32,962  
Gross Additions   36,765  
Gross Reductions   3,877  
Ending balance   65,850 32,962
Investment, Identifier [Axis]: SI East, LLC (Stavig), Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 237    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,250    
Gross Additions 3,750    
Gross Reductions 6,000    
Ending balance $ 0 2,250  
Investment, Identifier [Axis]: SI East, LLC (Stavig), Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 9.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (34)    
Amount of Interest, Fees or Dividends Credited to Income 8,409    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 63,600    
Gross Additions 31,159    
Gross Reductions 4,973    
Ending balance $ 89,786 $ 63,600  
Investment, Identifier [Axis]: SI East, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   10.25%  
Investment, Identifier [Axis]: SI East, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 9.50%    
Investment, Identifier [Axis]: SIB Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.00%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: SIB Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.01%    
Spread [3],[5] 6.25%    
Investment, Identifier [Axis]: SIB Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.01%    
Spread [3],[5] 6.25%    
Investment, Identifier [Axis]: SIB Holdings, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.01%    
Spread [3],[5] 6.25%    
Investment, Identifier [Axis]: SPAU Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 7.50%    
Investment, Identifier [Axis]: SPAU Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 11.06%    
Spread [3],[5] 7.50%    
Investment, Identifier [Axis]: Salient Partners L.P., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   7.00%  
Spread [2],[7]   6.00%  
Investment, Identifier [Axis]: Salient Partners L.P., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   6.00%  
Spread [2],[7]   5.00%  
Investment, Identifier [Axis]: Savers, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.34% [1],[4],[5] 6.25% [2],[7]  
Spread 5.50% [1],[4],[5] 5.50% [2],[7]  
Investment, Identifier [Axis]: Slick Innovations, LLC, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 264 180  
Amount of Interest, Fees or Dividends Credited to Income 456 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,510 1,330  
Gross Additions 264 180  
Gross Reductions 244 0  
Ending balance $ 1,530 $ 1,510 1,330
Investment, Identifier [Axis]: Slick Innovations, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 14.00% 13.00%  
Investment, Identifier [Axis]: Slick Innovations, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 14.00% 13.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 70 (42)  
Amount of Interest, Fees or Dividends Credited to Income 936 731  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,320 5,720  
Gross Additions 10,080 42  
Gross Reductions 1,560 442  
Ending balance 13,840 5,320 5,720
Investment, Identifier [Axis]: Slick Innovations, LLC, Warrants | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 1,219 0  
Amount of Unrealized Gain/(Loss) (219) 40  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 400 360  
Gross Additions 1,219 40  
Gross Reductions 1,619 0  
Ending balance 0 400 360
Investment, Identifier [Axis]: Sonic Systems International, LLC, Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (76) 0  
Amount of Interest, Fees or Dividends Credited to Income 43 37  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,070 0  
Gross Additions 286 1,070  
Gross Reductions 76 0  
Ending balance $ 1,280 $ 1,070 0
Investment, Identifier [Axis]: Sonic Systems International, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.24% [3],[5] 8.50% [7],[8]  
Spread 7.50% [3],[5] 7.50% [7],[8]  
Investment, Identifier [Axis]: Sonic Systems International, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 11.24% 8.50%  
Spread 7.50% 7.50%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 242 0  
Amount of Interest, Fees or Dividends Credited to Income 1,434 394  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,757 0  
Gross Additions 4,012 11,757  
Gross Reductions 0 0  
Ending balance $ 15,769 $ 11,757 0
Investment, Identifier [Axis]: South Coast Terminals Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.25%  
Spread [7],[8]   6.25%  
Investment, Identifier [Axis]: South Coast Terminals Holdings, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 5.75%    
Investment, Identifier [Axis]: South Coast Terminals Holdings, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 9.69%    
Spread [3],[5] 5.75%    
Investment, Identifier [Axis]: Staples Canada ULC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.83% [3],[5],[29],[30],[44] 8.00% [7],[8],[31],[32],[45]  
Spread 7.00% [3],[5],[29],[30],[44] 7.00% [7],[8],[31],[32],[45]  
Investment, Identifier [Axis]: Stellant Systems, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.05% [1],[4],[5] 6.25% [2],[7]  
Spread 5.50% [1],[4],[5] 5.50% [2],[7]  
Investment, Identifier [Axis]: Student Resource Center, LLC, Preferred Equity | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Student Resource Center, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.27% [3] 9.00% [7],[8]  
Spread 8.50% [3] 8.00% [7],[8]  
Investment, Identifier [Axis]: Student Resource Center, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.27%    
Spread 8.50%    
Investment, Identifier [Axis]: Student Resource Center, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 4,556    
Gross Reductions 0    
Ending balance 4,556 $ 0  
Investment, Identifier [Axis]: Student Resource Center, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) (5,991)    
Amount of Unrealized Gain/(Loss) 4,000    
Amount of Interest, Fees or Dividends Credited to Income 6    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 10,839    
Gross Additions 5,877    
Gross Reductions 16,716    
Ending balance 0 10,839  
Investment, Identifier [Axis]: Superior Rigging & Erecting Co., Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 4,500 4,500  
Gross Additions 0 0  
Gross Reductions 0 0  
Ending balance $ 4,500 $ 4,500 4,500
Investment, Identifier [Axis]: Superior Rigging & Erecting Co., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: Superior Rigging & Erecting Co., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 2,662 2,650  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 21,332 21,298  
Gross Additions 46 34  
Gross Reductions 0 0  
Ending balance $ 21,378 $ 21,332 21,298
Investment, Identifier [Axis]: Tacala Investment Corp., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 7.88% [5],[46],[47] 4.25% [7],[48]  
Spread 3.50% [5],[46],[47] 3.50% [7],[48]  
Investment, Identifier [Axis]: Team Public Choices, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.93% [1],[5] 6.00% [2],[7]  
Spread 5.00% [1],[5] 5.00% [2],[7]  
Investment, Identifier [Axis]: Tedder Industries, LLC, Preferred Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (1,564) 0  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,579 8,136  
Gross Additions 666 443  
Gross Reductions 1,564 0  
Ending balance 7,681 $ 8,579 8,136
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   2,009  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 16,181 16,301  
Gross Additions   2,280  
Gross Reductions   2,400  
Ending balance   16,181 16,301
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 215    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,040    
Gross Additions 800    
Gross Reductions 0    
Ending balance $ 1,840 1,040  
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Tedder Industries, LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (71)    
Amount of Interest, Fees or Dividends Credited to Income 1,900    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 15,141    
Gross Additions 51    
Gross Reductions 72    
Ending balance 15,120 15,141  
Investment, Identifier [Axis]: Televerde, LLC, Member Units | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (1,872)    
Amount of Interest, Fees or Dividends Credited to Income 2    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 7,280    
Gross Additions 0    
Gross Reductions 1,872    
Ending balance 5,408 7,280  
Investment, Identifier [Axis]: Televerde, LLC, Preferred Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 1,076    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 1,794    
Gross Reductions 0    
Ending balance 1,794 0  
Investment, Identifier [Axis]: The Affiliati Network, LLC, Preferred Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 0  
Amount of Interest, Fees or Dividends Credited to Income 403 270  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,400 0  
Gross Additions 0 6,400  
Gross Reductions 0 0  
Ending balance $ 6,400 6,400 0
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 0.13 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 32    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 262    
Gross Additions 3,764    
Gross Reductions 3,920    
Ending balance $ 106 262  
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 0.13 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 1,520    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 12,834    
Gross Additions 48    
Gross Reductions 3,440    
Ending balance $ 9,442 $ 12,834  
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 13.00% 7.00%  
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   11.83%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   842  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 12,834 0  
Gross Additions   13,873  
Gross Reductions   1,039  
Ending balance   $ 12,834 0
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 13.00% 11.83%  
Investment, Identifier [Axis]: The Affiliati Network, LLC, Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   7.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   9  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 262 0  
Gross Additions   1,462  
Gross Reductions   1,200  
Ending balance   262 0
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Common Stock | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (860) 2,630  
Amount of Interest, Fees or Dividends Credited to Income 116 116  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,660 6,030  
Gross Additions 0 2,630  
Gross Reductions 860 0  
Ending balance 7,800 $ 8,660 6,030
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Secured Debt | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   49  
Amount of Interest, Fees or Dividends Credited to Income   1,084  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,712 8,644  
Gross Additions   68  
Gross Reductions   0  
Ending balance   8,712 8,644
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 5    
Amount of Interest, Fees or Dividends Credited to Income 7    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance (8)    
Gross Additions 8    
Gross Reductions 0    
Ending balance $ 0 (8)  
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Investment, Identifier [Axis]: Trantech Radiator Topco, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (23)    
Amount of Interest, Fees or Dividends Credited to Income 1,044    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 8,720    
Gross Additions 23    
Gross Reductions 823    
Ending balance $ 7,920 $ 8,720  
Investment, Identifier [Axis]: U.S. TelePacific Corp., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.57% [1],[4],[5] 7.00% [2],[7]  
Spread 1.25% [1],[4],[5] 6.00% [2],[7]  
PIK Rate [1],[4],[5] 7.25%    
Investment, Identifier [Axis]: USA DeBusk LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.82% [3],[5] 6.75% [7],[8]  
Spread 5.75% [3],[5] 5.75% [7],[8]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Common Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance 0 $ 0  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock      
Schedule of Investments [Line Items]      
Total Rate [2]   19.00%  
PIK Rate [2]   19.00%  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   807  
Amount of Interest, Fees or Dividends Credited to Income   315  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 4,331 3,208  
Gross Additions   1,439  
Gross Reductions   316  
Ending balance   $ 4,331 3,208
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 1      
Schedule of Investments [Line Items]      
Total Rate 20.00% [1],[17] 20.00% [2],[15]  
PIK Rate 20.00% [1],[17] 20.00% [2],[15]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 20.00%    
PIK Rate 20.00%    
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 1 - 20.00% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (384)    
Amount of Interest, Fees or Dividends Credited to Income 384    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,832    
Gross Additions 385    
Gross Reductions 384    
Ending balance $ 2,833 $ 2,832  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 2      
Schedule of Investments [Line Items]      
Total Rate 20.00% [1] 20.00% [2]  
PIK Rate 20.00% [1] 20.00% [2]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 20.00%    
PIK Rate 20.00%    
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 2 - 20.00% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 493    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,498    
Gross Additions 493    
Gross Reductions 0    
Ending balance $ 1,991 $ 1,498  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 3      
Schedule of Investments [Line Items]      
Total Rate 19.00% [1] 13.50% [2]  
PIK Rate 19.00% [1] 13.50% [2]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 3 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 19.00%    
PIK Rate 19.00%    
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 3 - 19.00% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 4      
Schedule of Investments [Line Items]      
Total Rate [1] 13.50%    
PIK Rate [1] 13.50%    
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 4 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.50%    
PIK Rate 13.50%    
Investment, Identifier [Axis]: UniTek Global Services, Inc., Preferred Stock 4 - 19.00% | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Convertible Debt      
Schedule of Investments [Line Items]      
Total Rate 15.00% [1] 15.00% [2]  
PIK Rate 15.00% [1] 15.00% [2]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Convertible Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 15.00% 15.00%  
PIK Rate 15.00% 15.00%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) 1,011 1,178  
Amount of Interest, Fees or Dividends Credited to Income 269 151  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,375 0  
Gross Additions 2,217 2,461  
Gross Reductions 0 86  
Ending balance 4,592 $ 2,375 0
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate   8.50%  
Spread   5.50%  
PIK Rate   2.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   115  
Amount of Interest, Fees or Dividends Credited to Income   236  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 2,222 2,425  
Gross Additions   259  
Gross Reductions   462  
Ending balance   $ 2,222 2,425
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 10.76% [1],[4],[5] 8.50% [2],[7]  
Spread 5.50% [1],[4],[5] 5.50% [2],[7]  
PIK Rate 2.00% [1],[4],[5] 2.00% [2],[7]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Debt 1 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.76%    
Spread 5.50%    
PIK Rate 2.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 3    
Amount of Interest, Fees or Dividends Credited to Income 40    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 371    
Gross Additions 11    
Gross Reductions 0    
Ending balance $ 382 $ 371  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 10.76% [1],[4],[5] 8.50% [2],[7]  
Spread 5.50% [1],[4],[5] 5.50% [2],[7]  
PIK Rate 2.00% [1],[4],[5] 2.00% [2],[7]  
Investment, Identifier [Axis]: UniTek Global Services, Inc., Secured Debt 2 | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 10.76%    
Spread 5.50%    
PIK Rate 2.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 26    
Amount of Interest, Fees or Dividends Credited to Income 201    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,852    
Gross Additions 72    
Gross Reductions 212    
Ending balance 1,712 $ 1,852  
Investment, Identifier [Axis]: UnionRock Energy Fund II, LP, LP Interests | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss)   0  
Amount of Unrealized Gain/(Loss)   2,295  
Amount of Interest, Fees or Dividends Credited to Income   273  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,123 2,894  
Gross Additions   3,669  
Gross Reductions   440  
Ending balance   6,123 2,894
Investment, Identifier [Axis]: UnionRock Energy Fund II, LP, LP Interests | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) (174)    
Amount of Interest, Fees or Dividends Credited to Income 596    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 6,123    
Gross Additions 2,491    
Gross Reductions 2,759    
Ending balance 5,855 6,123  
Investment, Identifier [Axis]: Universal Wellhead Services Holdings, LLC, Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Universal Wellhead Services Holdings, LLC, Preferred Member Units      
Schedule of Investments [Line Items]      
Total Rate 14.00% [3],[18] 14.00% [8],[19]  
PIK Rate 14.00% [3],[18] 14.00% [8],[19]  
Investment, Identifier [Axis]: Universal Wellhead Services Holdings, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 14.00%    
PIK Rate 14.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 220    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 220    
Gross Reductions 0    
Ending balance 220 $ 0  
Investment, Identifier [Axis]: VORTEQ Coil Finishers, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.50%  
Spread [7],[8]   7.50%  
Investment, Identifier [Axis]: VVS Holdco LLC, Preferred Equity | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 $ 0  
Amount of Unrealized Gain/(Loss) 100 0  
Amount of Interest, Fees or Dividends Credited to Income 518 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 11,840 0  
Gross Additions 100 11,840  
Gross Reductions 0 0  
Ending balance $ 11,940 $ 11,840 0
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [7],[19]   7.00%  
Spread 6.00% [5],[6],[18] 6.00% [7],[19]  
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 1 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   11.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   913  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 30,100 0  
Gross Additions   30,100  
Gross Reductions   0  
Ending balance   30,100 0
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 1 - 6.00% | Other controlled investments      
Schedule of Investments [Line Items]      
Spread 6.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 55    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,169    
Gross Additions 811    
Gross Reductions 2,001    
Ending balance $ (21) $ 1,169  
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 11.50% [18] 11.50% [19]  
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 2 | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   7.00%  
Spread   6.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   7  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,169 0  
Gross Additions   1,169  
Gross Reductions   0  
Ending balance   1,169 0
Investment, Identifier [Axis]: VVS Holdco LLC, Secured Debt 2 - 11.50% | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate 11.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 3,606    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 30,100    
Gross Additions 61    
Gross Reductions 0    
Ending balance $ 30,161 $ 30,100  
Investment, Identifier [Axis]: Veregy Consolidated, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [2],[7]   6.25%  
Spread 5.25% [1],[5],[6] 5.25% [2],[7]  
Investment, Identifier [Axis]: Veregy Consolidated, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 10.41% [1],[5] 7.00% [2],[7]  
Spread 6.00% [1],[5] 6.00% [2],[7]  
Investment, Identifier [Axis]: Vida Capital, Inc, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.38% [1] 6.10% [2]  
Spread 6.00% [1] 6.00% [2]  
Investment, Identifier [Axis]: Vision Interests, Inc., Secured Debt | Other controlled investments      
Schedule of Investments [Line Items]      
Total Rate   13.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   244  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 0 2,028  
Gross Additions   0  
Gross Reductions   2,028  
Ending balance   0 2,028
Investment, Identifier [Axis]: Vision Interests, Inc., Series A Preferred Stock | Other controlled investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) 0 (160)  
Amount of Interest, Fees or Dividends Credited to Income 144 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 3,000 3,160  
Gross Additions 0 0  
Gross Reductions 0 160  
Ending balance 3,000 3,000 3,160
Investment, Identifier [Axis]: Volusion, LLC, Preferred Member Units | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0 0  
Amount of Unrealized Gain/(Loss) (5,990) 0  
Amount of Interest, Fees or Dividends Credited to Income 3 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 5,990 5,990  
Gross Additions 0 0  
Gross Reductions 5,990 0  
Ending balance $ 0 $ 5,990 5,990
Investment, Identifier [Axis]: Volusion, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 11.50% [16] 11.50% [12]  
Investment, Identifier [Axis]: Volusion, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 11.50% 11.50%  
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (1,821) 991  
Amount of Interest, Fees or Dividends Credited to Income 1,982 2,248  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 17,434 19,243  
Gross Additions 0 991  
Gross Reductions 2,520 2,800  
Ending balance $ 14,914 $ 17,434 19,243
Investment, Identifier [Axis]: Volusion, LLC, Unsecured Convertible Debt      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Investment, Identifier [Axis]: Volusion, LLC, Unsecured Convertible Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 8.00% 8.00%  
Amount of Realized Gain/(Loss) $ (143) $ 0  
Amount of Unrealized Gain/(Loss) (409) 118  
Amount of Interest, Fees or Dividends Credited to Income 33 33  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 409 291  
Gross Additions 0 118  
Gross Reductions 409 0  
Ending balance 0 409 291
Investment, Identifier [Axis]: Volusion, LLC, Warrants | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Wahoo Fitness Acquisition L.L.C., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 10.64% [1],[4],[5] 6.75% [2],[7]  
Spread 5.75% [1],[4],[5] 5.75% [2],[7]  
Investment, Identifier [Axis]: Wall Street Prep, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: Wall Street Prep, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 7.00%    
Investment, Identifier [Axis]: Wall Street Prep, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.74%    
Spread [3],[5] 7.00%    
Investment, Identifier [Axis]: Watterson Brands, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   7.25%  
Spread [7],[8]   6.25%  
Investment, Identifier [Axis]: Watterson Brands, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.73%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: Watterson Brands, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.73%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: Watterson Brands, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.73%    
Spread [3],[5] 6.00%    
Investment, Identifier [Axis]: West Star Aviation Acquisition, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[4],[5],[6] 6.00%    
Investment, Identifier [Axis]: West Star Aviation Acquisition, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 8.59%    
Spread [3],[4],[5] 6.00%    
Investment, Identifier [Axis]: Winter Services LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   8.00%  
Spread [7],[8]   7.00%  
Investment, Identifier [Axis]: Winter Services LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 7.00%    
Investment, Identifier [Axis]: Winter Services LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Spread [3],[5],[6] 7.00%    
Investment, Identifier [Axis]: Winter Services LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3],[5] 10.74%    
Spread [3],[5] 7.00%    
Investment, Identifier [Axis]: World Micro Holdings, LLC, Preferred Equity | Affiliate investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 3,845    
Gross Reductions 0    
Ending balance $ 3,845 $ 0  
Investment, Identifier [Axis]: World Micro Holdings, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Investment, Identifier [Axis]: World Micro Holdings, LLC, Secured Debt | Affiliate investments      
Schedule of Investments [Line Items]      
Total Rate 13.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 248    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 14,140    
Gross Reductions 0    
Ending balance $ 14,140 $ 0  
Investment, Identifier [Axis]: Xenon Arc, Inc., Secured Debt      
Schedule of Investments [Line Items]      
Total Rate [7],[8]   6.75%  
Spread [7],[8]   6.00%  
Investment, Identifier [Axis]: Xenon Arc, Inc., Secured Debt 1      
Schedule of Investments [Line Items]      
Spread [3],[6] 5.25%    
Investment, Identifier [Axis]: Xenon Arc, Inc., Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3] 10.84%    
Spread [3] 5.25%    
Investment, Identifier [Axis]: Xenon Arc, Inc., Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate [3] 8.63%    
Spread [3] 5.25%    
Investment, Identifier [Axis]: YS Garments, LLC, Secured Debt      
Schedule of Investments [Line Items]      
Total Rate 9.51% [1],[5] 6.50% [2],[7]  
Spread 5.50% [1],[5] 5.50% [2],[7]  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Preferred Member Units | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) $ 0 $ 0  
Amount of Unrealized Gain/(Loss) (1,890) 350  
Amount of Interest, Fees or Dividends Credited to Income 0 0  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,130 1,780  
Gross Additions 0 350  
Gross Reductions 1,890 0  
Ending balance $ 240 $ 2,130 1,780
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate 12.00% 12.00%  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 1 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   12.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   76  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 625 625  
Gross Additions   0  
Gross Reductions   0  
Ending balance   625 625
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 1 - 12.00% | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 12.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 71    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 625    
Gross Additions 0    
Gross Reductions 175    
Ending balance $ 450 $ 625  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate 6.50% 6.50%  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 2 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   14.00%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   0  
Amount of Interest, Fees or Dividends Credited to Income   390  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 2,750 2,750  
Gross Additions   0  
Gross Reductions   0  
Ending balance   2,750 2,750
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 2 - 6.50% | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 6.50%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (55)    
Amount of Interest, Fees or Dividends Credited to Income 66    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 1,000    
Gross Additions 0    
Gross Reductions 55    
Ending balance $ 945 $ 1,000  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 3      
Schedule of Investments [Line Items]      
Total Rate 14.00% 14.00%  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 3 | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate   6.50%  
Amount of Realized Gain/(Loss)   $ 0  
Amount of Unrealized Gain/(Loss)   21  
Amount of Interest, Fees or Dividends Credited to Income   66  
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance $ 1,000 979  
Gross Additions   21  
Gross Reductions   0  
Ending balance   1,000 $ 979
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Secured Debt 3 - 14.00% | Majority-owned investments      
Schedule of Investments [Line Items]      
Total Rate 14.00%    
Amount of Realized Gain/(Loss) $ 0    
Amount of Unrealized Gain/(Loss) (74)    
Amount of Interest, Fees or Dividends Credited to Income 390    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 2,750    
Gross Additions 0    
Gross Reductions 74    
Ending balance 2,676 2,750  
Investment, Identifier [Axis]: Ziegler’s NYPD, LLC, Warrants | Majority-owned investments      
Schedule of Investments [Line Items]      
Amount of Realized Gain/(Loss) 0    
Amount of Unrealized Gain/(Loss) 0    
Amount of Interest, Fees or Dividends Credited to Income 0    
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]      
Beginning balance 0    
Gross Additions 0    
Gross Reductions 0    
Ending balance $ 0 $ 0  
Investment, Identifier [Axis]: Zips Car Wash, LLC, Secured Debt 1      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5] 11.67%    
Spread [3],[4],[5] 7.25%    
Investment, Identifier [Axis]: Zips Car Wash, LLC, Secured Debt 2      
Schedule of Investments [Line Items]      
Total Rate [3],[4],[5],[47] 11.67%    
Spread [3],[4],[5],[47] 7.25%    
[1] Middle Market portfolio investment. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of Middle Market portfolio investments.
[2] Middle Market portfolio investment. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of Middle Market portfolio investments.
[3] Private Loan portfolio investment. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of Private Loan portfolio investments.
[4] A majority of the variable rate loans in the Company’s Investment Portfolio bear interest at a rate that may be determined by reference to either LIBOR (“L”), SOFR (“SF”) or an alternate Base rate (commonly based on the Federal Funds Rate or the Prime rate (“P”)), which typically resets every one, three, or six months at the borrower’s option. SOFR based contracts may include a credit spread adjustment (the “Adjustment”) that is charged in addition to the stated spread. The Adjustment is applied when the SOFR rate, plus the Adjustment, exceeds the stated floor rate, as applicable. As of December 31, 2022, SOFR based contracts in the portfolio had Adjustments ranging from 0.10% to 0.35%.
[5] Index based floating interest rate is subject to contractual minimum interest rate. As noted in this schedule, 66% of these floating rate loans (based on the par amount) contain LIBOR or Term SOFR (“SOFR”) floors which range between 0.50% and 2.00%, with a weighted-average floor of 1.04%.
[6] The position is unfunded and no interest income is being earned as of December 31, 2022. The position may earn a nominal unused facility fee on committed amounts.
[7] Index based floating interest rate is subject to contractual minimum interest rate. As noted in this schedule, 67% of these floating rate loans (based on the par amount) contain LIBOR floors which range between 0.50% and 2.00%, with a weighted-average LIBOR floor of 1.06%.
[8] Private Loan portfolio investment. See Note C—Fair Value Hierarchy for Investments — Portfolio Composition for a description of Private Loan portfolio investments.
[9] Non-accrual and non-income producing investment.
[10] Non-accrual and non-income producing investment.
[11] Index based floating interest rate is subject to contractual maximum base rate of 2.50%.
[12] Maturity date is under on-going negotiations with the portfolio company and other lenders, if applicable.
[13] The Company has entered into an intercreditor agreement that entitles the Company to the “last out” tranche of the first lien secured loans, whereby the “first out” tranche will receive priority as to the “last out” tranche with respect to payments of principal, interest, and any other amounts due thereunder. Therefore, the Company receives a higher interest rate than the contractual stated interest rate of SOFR+6.00% (Floor 1.00%) per the credit agreement and the Consolidated Schedule of Investments above reflects such higher rate.
[14] The Company has entered into an intercreditor agreement that entitles the Company to the “last out” tranche of the first lien secured loans, whereby the “first out” tranche will receive priority as to the “last out” tranche with respect to payments of principal, interest, and any other amounts due thereunder. Therefore, the Company receives a higher interest rate than the contractual stated interest rate of LIBOR+7.25% (Floor 1.25%) per the credit agreement and the Consolidated Schedule of Investments above reflects such higher rate.
[15] Income producing through dividends or distributions.
[16] Maturity date is under on-going negotiations with the portfolio company and other lenders, if applicable.
[17] Income producing through dividends or distributions.
[18] Shares/Units represent ownership in a related Real Estate or HoldCo entity.
[19] Shares/Units represent ownership in a related Real Estate or HoldCo entity.
[20] The Company has entered into an intercreditor agreement that entitles the Company to the “last out” tranche of the first lien secured loans, whereby the “first out” tranche will receive priority as to the “last out” tranche with respect to payments of principal, interest, and any other amounts due thereunder. Therefore, the Company receives a higher interest rate than the contractual stated interest rate of SOFR+8.00% (Floor 1.50%) per the credit agreement and the Consolidated Schedule of Investments above reflects such higher rate.
[21] The security has an effective contractual interest rate of 2.00% PIK + LIBOR+6.50%, Floor 1.00%, but the issuer may, in its discretion, elect to pay the PIK interest in cash. The rate presented represents the effective current yield based on actual payments received during the period.
[22] The security has an effective contractual interest rate of 2.00% PIK + LIBOR+6.50%, Floor 1.00%, but the issuer may, in its discretion, elect to pay the PIK interest in cash. The rate presented represents the effective current yield based on actual payments received during the period.
[23] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+6.25% (Floor 1.00%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[24] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+6.25% (Floor 1.00%). Due to an amendment and subsequent funding during the quarter, the term loan facility has different floating rate reset dates. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[25] As of December 31, 2022, borrowings under the loan facility bore interest at LIBOR+8.00% (Floor 1.00%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[26] The Company has entered into an intercreditor agreement that entitles the Company to the “last out” tranche of the first lien secured loans, whereby the “first out” tranche will receive priority as to the “last out” tranche with respect to payments of principal, interest, and any other amounts due thereunder. Therefore, the Company receives a higher interest rate than the contractual stated interest rate of LIBOR+7.96% (Floor 1.00%) per the credit agreement and the Consolidated Schedule of Investments above reflects such higher rate.
[27] Index based floating interest rate is subject to contractual maximum base rate of 1.50%.
[28] Index based floating interest rate is subject to contractual maximum index rate of 1.50% as of December 31, 2021.
[29] Investment is not a qualifying asset as defined under Section 55(a) of the 1940 Act. Qualifying assets must represent at least 70% of total assets at the time of acquisition of any additional non-qualifying assets.
[30] Portfolio company headquarters are located outside of the United States.
[31] Investment is not a qualifying asset as defined under Section 55(a) of the 1940 Act. Qualifying assets must represent at least 70% of total assets at the time of acquisition of any additional non-qualifying assets.
[32] Portfolio company headquarters are located outside of the United States.
[33] Other Portfolio investment. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of Other Portfolio investments.
[34] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+5.75% (Floor 1.00%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[35] As of December 31, 2022, borrowings under the loan facility bore interest at LIBOR+6.50% PIK or Prime+5.50% PIK. Revolving facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[36] As of December 31, 2021, borrowings under the loan facility bore interest at LIBOR+6.00% or Prime+5.00%. Delayed draw term loan facility permits the borrower to make an interest rate election on each new tranche of borrowings under the facility. The rate presented represents a weighted-average rate for borrowings under the facility.
[37] As of December 31, 2022, borrowings under the loan facility bore interest at LIBOR+10.00%. RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[38] As of December 31, 2022, borrowings under the loan facility bore interest at LIBOR+7.25% (Floor 0.75%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[39] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+8.00% (Floor 1.00%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[40] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+5.75% (Floor 1.00%). Delayed draw term loan facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[41] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+7.75% (Floor 1.25%). RLOC facility permits the borrower to make an interest rate election regarding the base rate on each draw under the facility. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[42] Portfolio company is in a bankruptcy process and, as such, the maturity date of our debt investment in this portfolio company will not be finally determined until such process is complete. As noted in footnote (14), our debt investment in this portfolio company is on non-accrual status.
[43] Portfolio company is in a bankruptcy process and, as such, the maturity date of our debt investment in this portfolio company will not be finally determined until such process is complete. As noted in footnote (14), our debt investment in this portfolio company is on non-accrual status.
[44] In connection with the Company’s debt investment in Staples Canada ULC and in an attempt to mitigate any potential adverse change in foreign exchange rates during the term of the Company’s investment, the Company maintains a forward foreign currency contract with Cadence Bank to lend $16.9 million Canadian Dollars and receive $13.1 million U.S. Dollars with a settlement date of September 14, 2023. The unrealized appreciation on the forward foreign currency contract was $0.6 million as of December 31, 2022.
[45] In connection with the Company’s debt investment in Staples Canada ULC and in an attempt to mitigate any potential adverse change in foreign exchange rates during the term of the Company’s investment, the Company maintains a forward foreign currency contract with Cadence Bank to lend $21.4 million Canadian Dollars and receive $16.9 million U.S. Dollars with a settlement date of September 14, 2022. The unrealized depreciation on the forward foreign currency contract was not significant as of December 31, 2021.
[46] Short-term portfolio investments. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of short-term portfolio investments.
[47] As of December 31, 2022, borrowings under the loan facility bore interest at SOFR+7.25% (Floor 1.00%). Each new draw on the delayed draw term loan facility has a different floating rate reset date. The rate presented represents a weighted-average rate for borrowings under the facility, as of December 31, 2022.
[48] Short-term portfolio investments. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of short-term portfolio investments.