Investments at Fair Value - Summary of Investments at Fair Value (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 2,792,773	$ 2,432,012
Fair Value	2,806,063	2,521,593
Net Unrealized Gain (Loss)	13,290	89,581
First-lien Debt Investments
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,548,902	2,265,555
Fair Value	2,538,586	2,298,856
Net Unrealized Gain (Loss)	(10,316)	33,301
Second-lien Debt Investments
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	42,725	42,629
Fair Value	41,197	42,729
Net Unrealized Gain (Loss)	(1,528)	100
Mezzanine Debt Investments
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	7,428	9,368
Fair Value	9,969	18,549
Net Unrealized Gain (Loss)	2,541	9,181
Equity And Other Investments
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	193,718	114,460
Fair Value	216,311	161,459
Net Unrealized Gain (Loss)	$ 22,593	$ 46,999