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

Fair Value of Financial Instruments - Schedule of Investments Measured at Fair Value on Recurring Basis (Details)

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Fair Value of Financial Instruments - Schedule of Investments Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments $ 4,459,584 $ 3,653,758
Accounts Payable and Accrued Liabilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other liabilities (87) (1,012)
Senior Secured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 4,209,798 3,419,044
Unsecured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 69,614 75,557
Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 52,735 53,802
Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 86,275 74,855
Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 41,162 30,500
Investment Funds & Vehicles measured at Net Asset Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 7,063 6,220
Total Investments, at fair value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 4,466,647 3,659,978
Derivative Instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 50 538
Total Investments including cash and cash equivalents and derivative instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 4,476,947 3,681,616
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 21,555 30,262
Quoted Prices in Active Markets for Identical Assets (Level 1) | Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 21,555 30,262
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 13,101 8,677
Significant Other Observable Inputs (Level 2) | Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 13,101 8,677
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 4,424,928 3,614,819
Significant Unobservable Inputs (Level 3) | Accounts Payable and Accrued Liabilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other liabilities (87) (1,012)
Significant Unobservable Inputs (Level 3) | Senior Secured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 4,209,798 3,419,044
Significant Unobservable Inputs (Level 3) | Unsecured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 69,614 75,557
Significant Unobservable Inputs (Level 3) | Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 52,735 53,802
Significant Unobservable Inputs (Level 3) | Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 64,720 44,593
Significant Unobservable Inputs (Level 3) | Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 28,061 21,823
Money Market Fund    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, fair value disclosure 10,250 21,100
Money Market Fund | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, fair value disclosure 10,250 21,100
Money Market Fund | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, fair value disclosure 0 0
Money Market Fund | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, fair value disclosure 0 0
Escrow Receivables/Escrow and Other Investment Receivables    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 168 152
Escrow Receivables/Escrow and Other Investment Receivables | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets $ 168 $ 152