v3.26.1
FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION - Schedule of Changes in Fair Value of Level 3 Portfolio Investments (Details) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance $ 5,496,705 $ 4,932,669
Transfers Into (Out of) Level 3 Hierarchy 0 (16,810)
Redemptions/ Repayments (501,658) (544,895)
New Investments 746,848 655,742
Other 0 0
Ending balance 5,722,612 5,071,513
Net change in unrealized appreciation (depreciation) on assets still held 28,141 16,589
Investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (55,117) (26,770)
Investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 35,834 71,577
Debt    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 3,607,331 3,278,365
Transfers Into (Out of) Level 3 Hierarchy 0 0
Redemptions/ Repayments (466,218) (514,216)
New Investments 686,358 575,433
Other (4,911) (30,773)
Ending balance 3,787,061 3,327,412
Net change in unrealized appreciation (depreciation) on assets still held (43,023) (9,904)
Debt | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 8,839 38,415
Debt | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (44,338) (19,812)
Equity    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 1,858,205 1,637,181
Transfers Into (Out of) Level 3 Hierarchy 0 (16,810)
Redemptions/ Repayments (35,440) (30,679)
New Investments 60,490 80,309
Other 4,911 30,773
Ending balance 1,906,042 1,719,038
Net change in unrealized appreciation (depreciation) on assets still held 72,824 18,553
Equity | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings (63,956) (65,185)
Equity | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 81,832 83,449
Equity Warrant    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 31,169 17,123
Transfers Into (Out of) Level 3 Hierarchy 0 0
Redemptions/ Repayments 0 0
New Investments 0 0
Other 0 0
Ending balance 29,509 25,063
Net change in unrealized appreciation (depreciation) on assets still held (1,660) 7,940
Equity Warrant | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings 0 0
Equity Warrant | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Gain (loss) included in earnings $ (1,660) $ 7,940