Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE HIERARCHY FOR INVESTMENTS???PORTFOLIO COMPOSITION - Summary of Investments (Details)

v3.22.2.2
FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Summary of Investments (Details)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2022
USD ($)
company
Dec. 31, 2021
USD ($)
company
Sep. 30, 2021
USD ($)
 [1],[4],[5]
Summary of Investment Holdings [Line Items]      
Cost $ 3,689,627 $ 3,259,246 [1],[2],[3] $ 3,689,627
Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 100.00% 100.00%  
Non-accrual Status | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 3.70% 3.30%  
Equity | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 13.90% 16.20%  
First lien debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 85.40% 82.50%  
LMM portfolio investments      
Summary of Investment Holdings [Line Items]      
Number of portfolio companies | company 75 73  
Fair value $ 1,910,900 $ 1,716,400  
Cost $ 1,593,700 $ 1,455,700  
Weighted-average annual effective yield 11.80% 11.20%  
Average EBITDA $ 7,700 $ 6,200  
Diluted equity ownership percentage 41.00% 40.00%  
Investment company, number of companies within portfolio excluded from EBITDA calculation | company 3 3  
LMM portfolio investments | Non-accrual Status      
Summary of Investment Holdings [Line Items]      
Weighted-average annual effective yield 11.10% 10.60%  
LMM portfolio investments | Debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 73.00% 70.90%  
LMM portfolio investments | Equity | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 27.00% 29.10%  
LMM portfolio investments | First lien debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 99.10% 99.00%  
Private Loan portfolio investments      
Summary of Investment Holdings [Line Items]      
Number of portfolio companies | company 87 75  
Fair value $ 1,476,900 $ 1,141,800  
Cost $ 1,523,800 $ 1,157,500  
Weighted-average annual effective yield 9.90% 8.20%  
Average EBITDA $ 41,900 $ 41,300  
Investment company, number of companies within portfolio excluded from EBITDA calculation | company 2 3  
Private Loan portfolio investments | Non-accrual Status      
Summary of Investment Holdings [Line Items]      
Weighted-average annual effective yield 9.60% 8.00%  
Private Loan portfolio investments | Debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 97.10% 95.70%  
Private Loan portfolio investments | Equity | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 2.90% 4.30%  
Private Loan portfolio investments | First lien debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 99.90% 98.70%  
Middle Market portfolio investments      
Summary of Investment Holdings [Line Items]      
Number of portfolio companies | company 33 36  
Fair value $ 354,300 $ 395,200  
Cost $ 419,400 $ 440,900  
Weighted-average annual effective yield 9.60% 7.50%  
Average EBITDA $ 70,700 $ 76,000  
Investment company, number of companies within portfolio excluded from EBITDA calculation | company   1  
Middle Market portfolio investments | Non-accrual Status      
Summary of Investment Holdings [Line Items]      
Weighted-average annual effective yield 9.10% 6.90%  
Middle Market portfolio investments | Debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 94.40% 93.30%  
Middle Market portfolio investments | Equity | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 5.60% 6.70%  
Middle Market portfolio investments | First lien debt | Investment Owned, At Cost | Investment Type Concentration Risk      
Summary of Investment Holdings [Line Items]      
Concentration risk, percentage 98.80% 98.70%  
[1] All investments are Lower Middle Market portfolio investments, unless otherwise noted. See Note C—Fair Value Hierarchy for Investments—Portfolio Composition for a description of Lower Middle Market portfolio investments. All of the Company’s investments, unless otherwise noted, are encumbered either as security for the Company’s Credit Facility or in support of the SBA-guaranteed debentures issued by the Funds.
[2] All portfolio company headquarters are based in the United States, unless otherwise noted.
[3] Principal is net of repayments. Cost is net of repayments and accumulated unearned income.
[4] All portfolio company headquarters are based in the United States, unless otherwise noted.
[5] 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.