Annual report [Section 13 and 15(d), not S-K Item 405]

FAIR VALUE HIERARCHY FOR INVESTMENTS???PORTFOLIO COMPOSITION - Schedule of Fair Value Hierarchy (Details)

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FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Schedule of Fair Value Hierarchy (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: $ 4,932,669 [1] $ 4,286,271 [2]
Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 4,932,669 4,286,271
Fair Value, Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 4,932,669 4,286,271
Fair Value, Recurring | LMM portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 2,502,872 2,273,000
Fair Value, Recurring | Private Loan portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 1,904,324 1,453,549
Fair Value, Recurring | Middle Market portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 155,329 243,695
Fair Value, Recurring | Other Portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 124,144 141,964
Fair Value, Recurring | External Investment Manager    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 246,000 174,063
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | LMM portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Private Loan portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Middle Market portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | External Investment Manager    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | LMM portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Private Loan portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Middle Market portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Other Portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | External Investment Manager    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 0 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 4,932,669 4,286,271
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | LMM portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 2,502,872 2,273,000
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Private Loan portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 1,904,324 1,453,549
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Middle Market portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 155,329 243,695
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Other Portfolio investments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: 124,144 141,964
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | External Investment Manager    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments at fair value: $ 246,000 $ 174,063
[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.