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

FAIR VALUE HIERARCHY FOR INVESTMENTS???PORTFOLIO COMPOSITION - Schedule of Changes in Fair Value of Level??3 Portfolio Investments (Details)

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FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Schedule of Changes in Fair Value of Level 3 Portfolio Investments (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance $ 4,286,271 $ 4,100,273
Transfers Into Level 3 Hierarchy 0 0
Redemptions/ Repayments (995,598) (938,613)
New Investments 1,506,951 892,879
Other 0 (82)
Ending balance 4,932,669 4,286,271
Investments | Net Changes from Unrealized to Realized    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (51,289) 118,212
Investments | Net Unrealized Appreciation (Depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 186,334 113,602
Debt    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 2,883,917 2,928,196
Transfers Into Level 3 Hierarchy 0 0
Redemptions/ Repayments (919,626) (891,359)
New Investments 1,368,567 800,838
Other (11,501) (43,888)
Ending balance 3,278,365 2,883,917
Debt | Net Changes from Unrealized to Realized    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 15,815 114,759
Debt | Net Unrealized Appreciation (Depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (58,807) (24,629)
Equity    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 1,395,744 1,166,643
Transfers Into Level 3 Hierarchy 0 0
Redemptions/ Repayments (75,972) (46,829)
New Investments 133,870 89,950
Other 11,501 46,382
Ending balance 1,637,181 1,395,744
Equity | Net Changes from Unrealized to Realized    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (66,994) 3,028
Equity | Net Unrealized Appreciation (Depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 239,032 136,570
Equity Warrant    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 6,610 5,434
Transfers Into Level 3 Hierarchy 0 0
Redemptions/ Repayments 0 (425)
New Investments 4,514 2,091
Other 0 (2,576)
Ending balance 17,123 6,610
Equity Warrant | Net Changes from Unrealized to Realized    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (110) 425
Equity Warrant | Net Unrealized Appreciation (Depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings $ 6,109 $ 1,661