Annual report pursuant to Section 13 and 15(d)

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) - Recurring - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments $ 3,653,758 $ 3,243,438
Accounts Payable and Accrued Liabilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other liabilities (1,012)  
Senior Secured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 3,419,044 2,987,577
Unsecured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 75,557 69,722
Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 53,802 53,038
Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 74,855 99,132
Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 30,500 33,969
Investment Funds & Vehicles measured at Net Asset Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 6,220 4,608
Total Investments, at fair value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 3,659,978 3,248,046
Derivative Instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 538 (766)
Total Investments including cash and cash equivalents and derivative instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 3,681,616 3,303,280
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 30,262 57,342
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 30,262 57,342
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 8,677 11,881
Significant Other Observable Inputs (Level 2) | Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments   0
Significant Other Observable Inputs (Level 2) | Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 8,677 11,881
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 3,614,819 3,174,215
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 (1,012)  
Significant Unobservable Inputs (Level 3) | Senior Secured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 3,419,044 2,987,577
Significant Unobservable Inputs (Level 3) | Unsecured Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 75,557 69,722
Significant Unobservable Inputs (Level 3) | Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 53,802 53,038
Significant Unobservable Inputs (Level 3) | Common Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 44,593 41,790
Significant Unobservable Inputs (Level 3) | Warrants    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 21,823 22,088
Money Market Fund    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, fair value disclosure 21,100 56,000
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 21,100 56,000
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 and Other Investment Receivables    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 152 10,888
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 $ 152 $ 10,888