v3.26.1
FAIR VALUE MEASUREMENTS - Level III Rollforward (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period $ 5,757,405 $ 5,626,978 $ 5,977,285 $ 5,506,793
Purchases of investments 259,693 [1] 498,263 [2] 419,175 [3] 922,376
Proceeds from principal repayments and sales of investments (561,995) [4] (219,684) [5] (897,452) [6] (524,330)
Accretion of discount/amortization of premium 6,012 5,284 11,725 11,422
Payment-in-kind 10,596 5,599 16,188 12,448
Debt and Equity Securities, Unrealized Gain (Loss)     (42,387) (29,616)
Transfers into/(out) of Level 3 (58,104) [7] (0) [8] (58,104) [9] 2,069
Fair value, end of period 5,486,823 5,907,542 5,486,823 5,907,542
Net change in unrealized appreciation (depreciation) from investments still held $ (16,747) $ (8,804) $ (40,576) $ (17,180)
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Non-controlled/non-affiliated investments Non-controlled/non-affiliated investments Non-controlled/non-affiliated investments Debt and Equity Securities, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ (25,464) $ 48 $ (55,589) $ (3,811)
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ (17,528) $ (8,946) $ (42,613) $ (19,425)
First Lien Debt        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 5,681,184 5,546,968 5,894,570 5,442,166
Purchases of investments 240,646 [1] 498,261 [2] 388,686 [3] 900,215
Proceeds from principal repayments and sales of investments (560,821) [4] (219,684) [5] (883,765) [6] (515,857)
Accretion of discount/amortization of premium 6,010 5,258 11,669 11,358
Payment-in-kind 5,193 4,386 9,155 10,865
Transfers into/(out) of Level 3 58,104 [7] 0 [8] 58,104 [9] 2,069
Fair value, end of period 5,390,820 5,828,001 5,390,820 5,828,001
Net change in unrealized appreciation (depreciation) from investments still held (13,230) (7,094) (30,318) (14,079)
First Lien Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (25,483) 48 (55,244) (6,930)
First Lien Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (14,013) (7,236) (32,355) (15,885)
Second Lien Debt        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 6,911 15,367 16,136 2,112
Purchases of investments 0 [1] 2 [2] 0 [3] 13,407
Proceeds from principal repayments and sales of investments (1) [4] 0 [5] (9,261) [6] 0
Accretion of discount/amortization of premium 0 0 1 1
Payment-in-kind 84 193 239 211
Transfers into/(out) of Level 3 0 [7] 0 [8] 0 [9] 0
Fair value, end of period 6,648 15,701 6,648 15,701
Net change in unrealized appreciation (depreciation) from investments still held (347) 139 (467) (30)
Second Lien Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) 0 0 0 0
Second Lien Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (346) 139 (467) (30)
Other Debt        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 7,380   11,564  
Purchases of investments [1] 0      
Proceeds from principal repayments and sales of investments 0 [4]   (3,253) [6]  
Accretion of discount/amortization of premium 2   55  
Payment-in-kind 271   566  
Net realized gains (losses) (1,066)      
Transfers into/(out) of Level 3 0 [7]   0 [9]  
Fair value, end of period 6,587   6,587  
Net change in unrealized appreciation (depreciation) from investments still held (1,066)   (1,980)  
Other Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses)     (365)  
Debt and Equity Securities, Unrealized Gain (Loss) 0      
Other Debt | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses)     (1,980)  
Equity [Member]        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 61,930 53,815 55,015 55,995
Purchases of investments 19,047 [1] 0 [2] 30,489 [3] 4,286
Proceeds from principal repayments and sales of investments (1,173) [4] 0 [5] (1,173) [6] (8,473)
Accretion of discount/amortization of premium 0 0 0 0
Payment-in-kind 5,048 746 6,228 966
Transfers into/(out) of Level 3 0 [7] 0 [8] 0 [9] 0
Fair value, end of period 82,768 52,782 82,768 52,782
Net change in unrealized appreciation (depreciation) from investments still held (2,104) (1,779) (7,811) (3,005)
Equity [Member] | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) 19 0 20 3,119
Equity [Member] | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ (2,103) (1,779) (7,811) (3,111)
Other Securities        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period   10,828   6,520
Purchases of investments   0 [2] $ 0 [3] 4,468
Proceeds from principal repayments and sales of investments   0 [5]   0
Accretion of discount/amortization of premium   26   63
Payment-in-kind   274   406
Transfers into/(out) of Level 3   0 [8]   0
Fair value, end of period   11,058   11,058
Net change in unrealized appreciation (depreciation) from investments still held   (70)   (66)
Other Securities | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses)   0   0
Other Securities | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses)   $ (70)   $ (399)
[1] Purchases may include investments received in corporate actions and restructurings
[2] Purchases may include investments received in corporate actions and restructurings.
[3] Purchases may include investments received in corporate actions and restructurings.
[4] Sales may include investments received in corporate actions and restructurings.
[5] Sales may include investments received in corporate actions and restructurings.
[6] Sales may include investments received in corporate actions and restructurings.
[7] Transfer of portfolio investments within the three-level hierarchy is recorded during the period of such reclassification occurrence at the fair value as of the beginning of the respective period. Generally, reclassifications are primarily due to increase/decrease of price transparency.
[8] Transfer of portfolio investments within the three-level hierarchy is recorded during the period of such reclassification occurrence at the fair value as of the beginning of the respective period. Generally, reclassifications are primarily due to increase/decrease of price transparency.
[9] Transfer of portfolio investments within the three-level hierarchy is recorded during the period of such reclassification occurrence at the fair value as of the beginning of the respective period. Generally, reclassifications are primarily due to increase/decrease of price transparency.