v3.26.1
Fair Value Measurements - Schedule of Reconciliation of the Beginning and Ending Balances for Investments at Fair Value that use Level 3 Inputs (Details)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
investment
Jun. 30, 2025
USD ($)
investment
Jun. 30, 2026
USD ($)
investment
Jun. 30, 2025
USD ($)
investment
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Fair value, asset, recurring basis, still held, unrealized gain (loss), statement of income or comprehensive income [extensible enumeration] Unrealized gain (loss) of investments Unrealized gain (loss) of investments Unrealized gain (loss) of investments Unrealized gain (loss) of investments
Total net change in unrealized gain (loss) on investments attributable to Level 3 investments still held $ 8,683 $ (9,034) $ (9,334) $ (10,596)
Number of investments transferred from Level 3 to Level 1 | investment 0 0 0 0
Investments        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Balance at the beginning $ 5,804,360 $ 4,520,484 $ 5,819,610 $ 4,008,824
Purchases of investments and other adjustments to cost 528,869 849,543 920,378 1,575,486
Proceeds from principal payments and sales of investments (368,769) (273,244) (745,634) (484,607)
Reclassifications 0 0 0 0
Balance at the end 5,956,254 5,087,528 5,956,254 5,087,528
Investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (28,915) (1,758) (40,649) (1,640)
Investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings 20,709 (7,497) 2,549 (10,535)
Senior secured loans        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Balance at the beginning 5,029,403 3,925,239 5,090,861 3,491,117
Purchases of investments and other adjustments to cost 446,027 735,543 772,420 1,341,538
Proceeds from principal payments and sales of investments (347,375) (244,817) (700,862) (411,296)
Reclassifications 1,375 (15,208) (15,655) (15,722)
Balance at the end 5,097,614 4,397,867 5,097,614 4,397,867
Senior secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (23,403) (2,133) (34,917) (1,991)
Senior secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (8,413) (757) (14,233) (5,779)
Unitranche secured loans        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Balance at the beginning 18,159 103,073 35,414 148,531
Purchases of investments and other adjustments to cost 2,206 67 2,224 410
Proceeds from principal payments and sales of investments 0 (262) (17,122) (44,810)
Reclassifications 0 0 0 0
Balance at the end 20,360 99,179 20,360 99,179
Unitranche secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings 0 0 0 0
Unitranche secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (5) (3,699) (156) (4,952)
Junior secured loans        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Balance at the beginning 320,109 254,222 277,025 177,677
Purchases of investments and other adjustments to cost 40,706 16,895 93,126 96,447
Proceeds from principal payments and sales of investments (19,397) (26,622) (23,962) (26,711)
Reclassifications 10,221 15,208 10,221 13,624
Balance at the end 343,146 256,158 343,146 256,158
Junior secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (2,677) (59) (2,942) (59)
Junior secured loans | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (5,816) (3,486) (10,322) (4,820)
Equity investments        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Balance at the beginning 436,689 237,950 416,310 191,499
Purchases of investments and other adjustments to cost 39,930 97,038 52,608 137,091
Proceeds from principal payments and sales of investments (1,997) (1,543) (3,688) (1,790)
Reclassifications (11,596) 0 5,434 2,098
Balance at the end 495,134 334,324 495,134 334,324
Equity investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings (2,835) 434 (2,790) 410
Equity investments | Income Statement Location [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs        
Gains (losses) included in earnings $ 34,943 $ 445 $ 27,260 $ 5,016