Quarterly report [Sections 13 or 15(d)]

FAIR VALUE HIERARCHY FOR INVESTMENTS???PORTFOLIO COMPOSITION - Narrative (Details)

v3.25.3
FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Narrative (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended 15 Months Ended
Sep. 30, 2025
USD ($)
company
investmentManager
entity
investment
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
company
investmentManager
entity
investment
Sep. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
investmentManager
company
investment
entity
Sep. 30, 2025
USD ($)
company
investmentManager
entity
investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Expenses allocated $ 5,734 $ 5,322 $ 16,962 $ 16,768    
Annualized total return on investments (as a percent) 0.169 0.177 0.164 0.167    
Achieved total return on investments (as a percent)         0.179  
Fair value $ 5,147,773 [1],[2],[3]   $ 5,147,773 [1],[2],[3]   $ 4,932,669 [4],[5],[6] $ 5,147,773 [1],[2],[3]
Cost 4,345,983 [1],[3],[7]   $ 4,345,983 [1],[3],[7]   $ 4,237,312 [4],[6],[8] $ 4,345,983 [1],[3],[7]
Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     100.00%   100.00%  
Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     100.00%   100.00%  
External Investment Manager | Affiliated Entity            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Expenses allocated $ 5,700 $ 5,300 $ 17,000 $ 16,800    
Short-term portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of portfolio investments | investment 0   0   0 0
Short-term portfolio investments | Maximum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     1 year      
LMM portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of portfolio companies | company 88   88   84 88
Fair value $ 2,782,200   $ 2,782,200   $ 2,502,900 $ 2,782,200
Cost $ 2,167,500   $ 2,167,500   $ 1,937,800 $ 2,167,500
LMM portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent) 27.00% 24.00%       92.00%
LMM portfolio investments | Debt | Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     70.70%   70.80%  
LMM portfolio investments | Minimum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Annual revenues     $ 10,000      
Investments $ 5,000   $ 5,000     $ 5,000
LMM portfolio investments | Minimum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     5 years      
LMM portfolio investments | Maximum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Annual revenues     $ 150,000      
Investments $ 125,000   $ 125,000     $ 125,000
LMM portfolio investments | Maximum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     7 years      
Private Loan portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of portfolio companies | company 86   86   91 86
Fair value $ 1,886,500   $ 1,886,500   $ 1,904,300 $ 1,886,500
Cost $ 1,898,300   $ 1,898,300   $ 1,952,500 $ 1,898,300
Private Loan portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent) 26.00% 24.00%       94.00%
Private Loan portfolio investments | Debt | Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     94.00%   95.40%  
Private Loan portfolio investments | Minimum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Annual revenues     $ 25,000      
Investments $ 10,000   $ 10,000     $ 10,000
Private Loan portfolio investments | Minimum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     3 years      
Private Loan portfolio investments | Maximum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Annual revenues     $ 500,000      
Investments $ 100,000   $ 100,000     $ 100,000
Private Loan portfolio investments | Maximum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     7 years      
Middle Market portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of portfolio companies | company 11   11   15 11
Fair value $ 89,900   $ 89,900   $ 155,300 $ 89,900
Cost 119,800   $ 119,800   $ 195,000 119,800
Middle Market portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     1.70%   3.10%  
Middle Market portfolio investments | Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     2.80%   4.60%  
Middle Market portfolio investments | Minimum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investments 3,000   $ 3,000     3,000
Middle Market portfolio investments | Minimum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     3 years      
Middle Market portfolio investments | Maximum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investments 25,000   $ 25,000     25,000
Middle Market portfolio investments | Maximum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     7 years      
Other Portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair value 122,800   $ 122,800   $ 124,100 122,800
Cost $ 130,900   $ 130,900   $ 122,500 $ 130,900
Number of portfolio investments in entities | entity 32   32   31 32
Number of investment managers | investmentManager 12   12   12 12
Other Portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     2.40%   2.50%  
Other Portfolio investments | Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     3.00%   2.90%  
Other Portfolio investments | Minimum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     5 years      
Other Portfolio investments | Maximum | Debt            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment term (in years)     10 years      
External Investment Manager            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair value $ 266,400   $ 266,400   $ 246,000 $ 266,400
Cost $ 29,500   $ 29,500   $ 29,500 $ 29,500
External Investment Manager | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     5.20%   5.00%  
External Investment Manager | Investment Owned, At Cost | Investment Type Concentration Risk            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Concentration risk (as a percent)     0.70%   0.70%  
[1] All portfolio company headquarters are based in the United States, unless otherwise noted.
[2] Investment Fair Value was determined using significant unobservable inputs, unless otherwise noted. See Note C — Fair Value Hierarchy for Investments —Portfolio Composition for further discussion. Negative fair value is the result of the capitalized discount on the loan or the unfunded commitment being valued below par.
[3] All investments are LMM (as defined below) portfolio investments, unless otherwise noted. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of LMM portfolio investments. All of the Company’s investments, unless otherwise noted, are encumbered either as security for
the Corporate Facility or SPV Facility (each as defined below) or in support of the debentures guaranteed by the SBA (as defined below) and issued by the Funds (as defined below).
[4] All portfolio company headquarters are based in the United States, unless otherwise noted.
[5] Investment Fair Value was determined using significant unobservable inputs, unless otherwise noted. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for further discussion. Negative fair value is the result of the capitalized discount on the loan or the unfunded commitment being valued below par.
[6] All investments are LMM portfolio investments, unless otherwise noted. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for a description of LMM portfolio investments. All of the Company’s investments, unless otherwise noted, are encumbered either as security for the Corporate Facility or SPV Facility or in support of the debentures guaranteed by the SBA and issued by the Funds.
[7] Principal is net of repayments. Cost is net of repayments and accumulated unearned income. Negative cost is the result of the capitalized discount being greater than the principal amount outstanding on the loan.
[8] Principal is net of repayments. Cost is net of repayments and accumulated unearned income. Negative cost is the result of the capitalized discount being greater than the principal amount outstanding on the loan.