Quarterly report pursuant to Section 13 or 15(d)

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

v3.23.3
FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Narrative (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2023
USD ($)
entity
company
Sep. 30, 2022
USD ($)
Sep. 30, 2023
USD ($)
entity
company
Sep. 30, 2022
USD ($)
Sep. 30, 2023
USD ($)
entity
company
Dec. 31, 2022
USD ($)
company
entity
investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Expenses allocated $ 5,404 $ 3,334 $ 16,089 $ 9,613    
Annualized total return on investments (as a percent) 0.160 0.105 0.154 0.096    
Achieved total return on investments (as a percent)           0.111
Fair value $ 4,294,722 [1]   $ 4,294,722 [1]   $ 4,294,722 [1] $ 4,102,177 [2]
Cost 3,799,385 [3]   $ 3,799,385 [3]   $ 3,799,385 [3] $ 3,773,752 [4]
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%
Affiliated Entity | External Investment Manager            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Expenses allocated $ 5,400 $ 3,300 $ 16,100 $ 9,600    
Short-term portfolio investments            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of investments | investment           1
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 79   79   79 78
Fair value $ 2,190,400   $ 2,190,400   $ 2,190,400 $ 2,060,500
Cost $ 1,716,900   $ 1,716,900   $ 1,716,900 $ 1,719,900
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) 22.00% 24.00%     94.00%  
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)     71.90%     73.70%
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 $ 75,000   $ 75,000   $ 75,000  
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 89   89   89 85
Fair value $ 1,544,000   $ 1,544,000   $ 1,544,000 $ 1,471,500
Cost $ 1,577,500   $ 1,577,500   $ 1,577,500 $ 1,500,300
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) 25.00% 20.00%     83.00%  
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)     96.20%     97.10%
Private Loan portfolio investments | Minimum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
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]            
Investments $ 75,000   $ 75,000   $ 75,000  
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 27   27   27 31
Fair value $ 290,600   $ 290,600   $ 290,600 $ 329,100
Cost 343,300   $ 343,300   343,300 $ 401,700
Middle Market 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)     92.70%     93.80%
Middle Market portfolio investments | Minimum            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Annual revenues     $ 150,000      
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]            
Annual revenues     $ 1,500,000      
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]            
Number of portfolio companies | entity 15   15   15 14
Fair value $ 123,600   $ 123,600   $ 123,600 $ 116,300
Cost 132,200   $ 132,200   132,200 $ 120,400
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)     2.90%     2.80%
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)     3.50%     3.20%
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 146,100   $ 146,100   146,100 $ 122,900
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)     3.40%     3.00%
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)     0.80%     0.80%
[1] 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.
[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] 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.
[4] 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.