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 $ 3,518,646 $ 3,728,366 $ 3,711,453 $ 3,686,956
Purchases of investments 152,870 [1] 204,003 [2] 267,201 [3] 414,587 [2]
Proceeds from principal repayments and sales of investments (251,890) [4] (207,470) [5] (526,582) [4] (414,261) [6]
Accretion of discount/amortization of premium 3,393 3,823 6,893 8,088
Payment-in-kind 6,454 4,118 11,338 9,054
Transfers into/(out) of Level 3 14,001 [7] 0 [8] 14,438 [9] 43,745 [8]
Fair value, end of period 3,412,178 3,726,935 3,412,178 3,726,935
Net change in unrealized appreciation (depreciation) from investments still held $ (24,038) $ (5,535) $ (53,254) $ (18,180)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction Price Change, Operating, after Tax Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction Price Change, Operating, after Tax Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction Price Change, Operating, after Tax Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction Price Change, Operating, after Tax
Net change in unrealized appreciation (depreciation)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ (24,038) $ (5,932) $ (52,133) $ (21,821)
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 non-controlled/non-affiliated investments Net change in unrealized appreciation (depreciation) on non-controlled/non-affiliated investments Net change in unrealized appreciation (depreciation) on non-controlled/non-affiliated investments Net change in unrealized appreciation (depreciation) on non-controlled/non-affiliated investments
Net realized gains (losses)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ (7,258) $ 27 $ (20,430) $ 587
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net Realized Gain (Loss) Net Realized Gain (Loss) Net Realized Gain (Loss) Net Realized Gain (Loss)
First Lien Debt [Member]        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period $ 3,421,628 $ 3,631,679 $ 3,611,829 $ 3,603,209
Purchases of investments 145,645 [1] 204,003 [2] 255,701 [3] 409,348 [2]
Proceeds from principal repayments and sales of investments (251,436) [4] (207,470) [5] (521,885) [4] (410,112) [6]
Accretion of discount/amortization of premium 3,363 3,796 6,753 8,028
Payment-in-kind 3,926 3,091 6,918 7,018
Transfers into/(out) of Level 3 14,001 [7] 0 [8] 14,438 [9] 30,168 [8]
Fair value, end of period 3,305,047 3,630,247 3,305,047 3,630,247
Net change in unrealized appreciation (depreciation) from investments still held (24,815) (4,482) (49,413) (13,796)
First Lien Debt [Member] | Net change in unrealized appreciation (depreciation)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (24,815) (4,879) (49,769) (16,067)
First Lien Debt [Member] | Net realized gains (losses)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (7,265) (27) (18,938) (1,345)
Second Lien Debt [Member]        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 49,192 49,212 51,097 33,351
Purchases of investments 0 [1] 0 [2] 0 [3] 3,064 [2]
Proceeds from principal repayments and sales of investments 0 [4] 0 [5] (2,116) [4] 0 [6]
Accretion of discount/amortization of premium 27 21 111 50
Payment-in-kind 685 278 1,382 516
Transfers into/(out) of Level 3 0 [7] 0 [8] 0 [9] 13,577 [8]
Fair value, end of period 52,861 49,743 52,861 49,743
Net change in unrealized appreciation (depreciation) from investments still held 2,957 232 2,387 (814)
Second Lien Debt [Member] | Net change in unrealized appreciation (depreciation)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) 2,957 232 2,387 (815)
Second Lien Debt [Member] | Net realized gains (losses)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) 0 0 0 0
Other Debt Investments [Member]        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 7,593 9,603 10,114 9,198
Purchases of investments 0 [1] 0 [2] 0 [3] 1,021 [2]
Proceeds from principal repayments and sales of investments 0 [4] 0 [5] (2,127) [4] 0 [6]
Accretion of discount/amortization of premium 3 6 29 10
Payment-in-kind 280 267 569 493
Transfers into/(out) of Level 3 0 [7] 0 [8] 0 [9] 0 [8]
Fair value, end of period 7,149 9,773 7,149 9,773
Net change in unrealized appreciation (depreciation) from investments still held (727) (103) (1,414) (949)
Other Debt Investments [Member] | Net change in unrealized appreciation (depreciation)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (727) (103) 63 (949)
Other Debt Investments [Member] | Net realized gains (losses)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) 0 0 (1,499) 0
Equity Investments        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning of period 40,233 37,872 38,413 41,198
Purchases of investments 7,225 [1] 0 [2] 11,500 [3] 1,154 [2]
Proceeds from principal repayments and sales of investments (454) [4] 0 [5] (454) [4] (4,149) [6]
Accretion of discount/amortization of premium 0 0 0 0
Payment-in-kind 1,563 482 2,469 1,027
Transfers into/(out) of Level 3 0 [7] 0 [8] 0 [9] 0 [8]
Fair value, end of period 47,121 37,172 47,121 37,172
Net change in unrealized appreciation (depreciation) from investments still held (1,453) (1,182) (4,814) (2,621)
Equity Investments | Net change in unrealized appreciation (depreciation)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) (1,453) (1,182) (4,814) (3,990)
Equity Investments | Net realized gains (losses)        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Net realized gains (losses) $ 7 $ 0 $ 7 $ 1,932
[1] Purchases may include investments received in corporate action and restructurings.
[2] Purchases may include investments received in corporate action and restructurings.
[3] Purchases may include investments received in corporate action and restructurings.
[4] Sales may include investments received in corporate action and restructurings.
[5] Sales may include investments received in corporate action and restructurings.
[6] Sales may include investments received in corporate action 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.