v3.25.4
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
12 Months Ended
Dec. 31, 2025
USD ($)
investment
Dec. 31, 2024
USD ($)
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
Total net change in unrealized gain (loss) on investments attributable to Level 3 investments still held $ (96,673) $ (4,494)
Number of investments transferred from Level 3 to Level 1 | investment 0 1
Investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Balance at the beginning $ 4,008,824 $ 2,528,144
Purchases of investments and other adjustments to cost 2,872,097 2,152,781
Proceeds from principal payments and sales of investments (956,190) (673,119)
Reclassifications 0 0
Transfers in (out) of Level 3   (133)
Balance at the end 5,819,610 4,008,824
Investments | Net realized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (5,329) 59
Investments | Net change in unrealized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (99,792) 1,092
Senior secured loans    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Balance at the beginning 3,491,117 2,171,243
Purchases of investments and other adjustments to cost 2,527,221 1,981,176
Proceeds from principal payments and sales of investments (817,050) (601,460)
Reclassifications (62,958) (66,491)
Transfers in (out) of Level 3   0
Balance at the end 5,090,861 3,491,117
Senior secured loans | Net realized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (2,768) (98)
Senior secured loans | Net change in unrealized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (44,701) 6,747
Unitranche secured loans    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Balance at the beginning 148,531 184,853
Purchases of investments and other adjustments to cost 487 8,269
Proceeds from principal payments and sales of investments (91,213) (44,879)
Reclassifications (16,642) 0
Transfers in (out) of Level 3   0
Balance at the end 35,414 148,531
Unitranche secured loans | Net realized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings 0 0
Unitranche secured loans | Net change in unrealized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (5,749) 288
Junior secured loans    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Balance at the beginning 177,677 87,986
Purchases of investments and other adjustments to cost 142,213 78,335
Proceeds from principal payments and sales of investments (43,174) (22,839)
Reclassifications 53,866 45,802
Transfers in (out) of Level 3   0
Balance at the end 277,025 177,677
Junior secured loans | Net realized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (3,142) 39
Junior secured loans | Net change in unrealized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings (50,415) (11,646)
Equity investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Balance at the beginning 191,499 84,062
Purchases of investments and other adjustments to cost 202,176 85,001
Proceeds from principal payments and sales of investments (4,753) (3,941)
Reclassifications 25,734 20,689
Transfers in (out) of Level 3   (133)
Balance at the end 416,310 191,499
Equity investments | Net realized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings 581 118
Equity investments | Net change in unrealized gain (loss) on investments    
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs    
Gains (losses) included in earnings $ 1,073 $ 5,703