v3.26.1
FAIR VALUE MEASUREMENTS - Schedule of Level 3 Input Reconciliation (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, beginning of period $ 2,463,922 $ 1,739,546
Purchases 238,100 176,510
Sales (164,859) (158,337)
Paydowns (229,290) (187,106)
Accretion of discount 2,513 2,968
Transfers Out of Level 3 (276)  
Balance, end of period 2,276,829 2,245,626
Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations $ (30,914) $ (8,192)
Fair Value, Asset, Recurring, Basis Still Held, Unrealized Gain (Loss), Statement Of Income, Extensible List, Not Disclosed Flag Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations
CSL III Merger    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   $ 485,673
Credit Fund II Purchase    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   191,201
Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings $ (9,482) $ (7,027)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net realized gain (loss) on investments Net realized gain (loss) on investments
Net change in unrealized appreciation (depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings $ (23,799) $ 2,198
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net change in unrealized appreciation (depreciation) on investments Net change in unrealized appreciation (depreciation) on investments
First Lien Debt    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, beginning of period $ 2,061,847 $ 1,323,697
Purchases 198,327 171,923
Sales (162,853) (88,285)
Paydowns (177,088) (187,006)
Accretion of discount 2,271 2,749
Transfers Out of Level 3 0  
Balance, end of period 1,899,631 1,873,091
Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations (21,344) (13,947)
First Lien Debt | CSL III Merger    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   479,124
First Lien Debt | Credit Fund II Purchase    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   181,645
First Lien Debt | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings (9,469) 925
First Lien Debt | Net change in unrealized appreciation (depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings (13,404) (11,681)
Second Lien Debt    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, beginning of period 95,130 116,467
Purchases 1,065 989
Sales (15) (1,137)
Paydowns (11,702) (100)
Accretion of discount 228 160
Transfers Out of Level 3 0  
Balance, end of period 78,325 129,629
Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations (5,998) (386)
Second Lien Debt | CSL III Merger    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   4,117
Second Lien Debt | Credit Fund II Purchase    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   9,493
Second Lien Debt | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings (310) (7,974)
Second Lien Debt | Net change in unrealized appreciation (depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings (6,071) 7,614
Equity Investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, beginning of period 143,331 116,746
Purchases 18,909 3,598
Sales (1,991) (6,415)
Paydowns 0 0
Accretion of discount 14 59
Transfers Out of Level 3 (276)  
Balance, end of period 156,091 121,515
Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations (3,441) 4,886
Equity Investments | CSL III Merger    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   2,432
Equity Investments | Credit Fund II Purchase    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   63
Equity Investments | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings 297 22
Equity Investments | Net change in unrealized appreciation (depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings (4,193) 5,010
Investment Funds    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, beginning of period 163,614 182,636
Purchases 19,799 0
Sales 0 (62,500)
Paydowns (40,500) 0
Accretion of discount 0 0
Transfers Out of Level 3 0  
Balance, end of period 142,782 121,391
Net change in unrealized appreciation (depreciation) relating to Level 3 investments still held at the reporting date and included within the Consolidated Statements of Operations (131) 1,255
Investment Funds | CSL III Merger    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   0
Investment Funds | Credit Fund II Purchase    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Transfers in   0
Investment Funds | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings 0 0
Investment Funds | Net change in unrealized appreciation (depreciation)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net gains (losses) included in earnings $ (131) $ 1,255