v3.25.0.1
Investments - Fair Value, Assets Measured on Recurring Basis (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Sep. 30, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Principal $ 8,212,796 $ 7,830,886
Amortized Cost 8,755,566 8,302,913
Fair Value 8,685,231 [1] 8,235,411 [2]
Senior secured    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Principal 481,445 510,503
Amortized Cost 481,012 506,178
Fair Value 476,601 502,386
One stop    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Principal 7,670,400 7,271,543
Amortized Cost 7,646,607 7,216,368
Fair Value 7,543,323 7,110,258
Second lien    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Principal 29,621 18,430
Amortized Cost 28,069 17,125
Fair Value 25,086 14,054
Subordinated debt    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Principal 31,330 30,410
Amortized Cost 31,058 29,943
Fair Value 31,246 30,175
Equity    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Amortized Cost 568,820 533,299
Fair Value $ 608,975 $ 578,538
[1] The fair values of investments were valued using significant unobservable inputs, unless noted otherwise. See “Note 6. Fair Value Measurements”.
[2] The fair values of investments were valued using significant unobservable inputs, unless noted otherwise. See “Note 6. Fair Value Measurements”.