v3.26.1
Fair Value of Financial Instruments - Schedule of Changes in the Fair Value of Investments (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Total    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period $ 30,479,543 $ 21,098,813
Purchases of investments, net 1,758,188 3,036,483
Payment-in-kind 43,541 35,248
Proceeds from investments, net (1,270,468) (524,090)
Net amortization/accretion of discount/premium on investments 21,806 20,090
Transfers between investment types   0
Transfers into (out of) Level 3 (158,086) (76,391)
Fair Value, End of Period 30,587,040 23,600,920
Total | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (272,571) 69,832
Total | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (14,913) (59,065)
First-lien senior secured    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 27,529,166 19,332,178
Purchases of investments, net 1,713,080 2,885,586
Payment-in-kind 20,487 13,840
Proceeds from investments, net (1,224,478) (487,004)
Net amortization/accretion of discount/premium on investments 21,065 18,707
Transfers between investment types   (5,543)
Transfers into (out of) Level 3 (90,830) (131,882)
Fair Value, End of Period 27,737,177 21,628,557
First-lien senior secured | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (223,599) 44,804
First-lien senior secured | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (7,714) (42,129)
Second-lien senior secured debt investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 1,105,661 451,426
Purchases of investments, net 0 19,901
Payment-in-kind 3,864 2,268
Proceeds from investments, net 0 (7,600)
Net amortization/accretion of discount/premium on investments 275 198
Transfers between investment types   0
Transfers into (out of) Level 3 (67,606) 59,547
Fair Value, End of Period 1,020,719 516,554
Second-lien senior secured debt investments | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (21,475) 2,159
Second-lien senior secured debt investments | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) 0 (11,345)
Unsecured debt investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 479,850 366,496
Purchases of investments, net 0 0
Payment-in-kind 8,213 10,725
Proceeds from investments, net (42,371) (369)
Net amortization/accretion of discount/premium on investments 202 557
Transfers between investment types   0
Transfers into (out of) Level 3 0 0
Fair Value, End of Period 439,084 383,588
Unsecured debt investments | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (10,502) 12,045
Unsecured debt investments | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) 3,692 (5,866)
Specialty finance    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 134,800 90,736
Purchases of investments, net 0 13,526
Payment-in-kind 2,241 305
Proceeds from investments, net (245) 0
Net amortization/accretion of discount/premium on investments 0 0
Transfers between investment types   0
Transfers into (out of) Level 3 0 0
Fair Value, End of Period 136,796 104,262
Specialty finance | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) 0 (305)
Specialty finance | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) 0 0
Preferred    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 496,312 359,901
Purchases of investments, net 9,879 85,419
Payment-in-kind 8,703 8,079
Proceeds from investments, net (2,232) (27,777)
Net amortization/accretion of discount/premium on investments 264 628
Transfers between investment types   3,817
Transfers into (out of) Level 3 0 0
Fair Value, End of Period 506,595 431,404
Preferred | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) 1,736 1,062
Preferred | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (8,067) 275
Common    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 291,027 206,420
Purchases of investments, net 32,890 10,841
Payment-in-kind 33 31
Proceeds from investments, net (1,142) (13)
Net amortization/accretion of discount/premium on investments 0 0
Transfers between investment types   1,726
Transfers into (out of) Level 3 350 (4,056)
Fair Value, End of Period 305,124 214,793
Common | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (15,210) (156)
Common | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (2,824) 0
Specialty finance    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of period 442,727 291,656
Purchases of investments, net 2,339 21,210
Payment-in-kind 0 0
Proceeds from investments, net 0 (1,327)
Net amortization/accretion of discount/premium on investments 0 0
Transfers between investment types   0
Transfers into (out of) Level 3 0 0
Fair Value, End of Period 441,545 321,762
Specialty finance | Net change in unrealized gain (loss)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) (3,521) 10,223
Specialty finance | Net realized gains (losses)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Net change in unrealized gain (loss) / realized gain (loss) $ 0 $ 0