Agreements and Related Party Transactions - Summary of Investments in Non-controlled Affiliates (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	$ 1,582,075
Fair Value, Ending balance	1,610,775
Non-controlled Affiliated Investments
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	52,619	$ 43,080
Gross Additions	1,392	15,531
Gross Reductions	(3,183)	(314)
Change in Unrealized Gains/ (Losses)	1,195	539
Fair Value, Ending balance	52,023	58,836
Dividend, Interest, PIK and Other Income	2,603	2,915
Non-controlled Affiliated Investments | AX VI INV2 Holding AB
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	14,152	12,117
Gross Additions	631	1,394
Gross Reductions		(46)
Change in Unrealized Gains/ (Losses)	648	752
Fair Value, Ending balance	15,431	14,217
Dividend, Interest, PIK and Other Income	767	551
Non-controlled Affiliated Investments | ASP MCS Acquisition Corp.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	799	826
Gross Additions	347	110
Gross Reductions	(1)	(1)
Change in Unrealized Gains/ (Losses)	108	26
Fair Value, Ending balance	1,253	961
Dividend, Interest, PIK and Other Income	19	16
Non-controlled Affiliated Investments | Bayside Opco, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	6,704
Gross Additions	189
Gross Reductions	(13)
Change in Unrealized Gains/ (Losses)	695
Fair Value, Ending balance	7,575
Dividend, Interest, PIK and Other Income	386
Non-controlled Affiliated Investments | GACP II LP
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	3,927	4,889
Gross Reductions	(2,855)	(193)
Change in Unrealized Gains/ (Losses)	(373)	(46)
Fair Value, Ending balance	699	4,650
Dividend, Interest, PIK and Other Income		474
Non-controlled Affiliated Investments | Isagenix International, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	2,546
Gross Additions	147	2,509
Change in Unrealized Gains/ (Losses)	(36)	(10)
Fair Value, Ending balance	2,657	2,499
Dividend, Interest, PIK and Other Income	186	27
Non-controlled Affiliated Investments | Slickdeals Holdings, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	15,192	15,433
Gross Additions	55	40
Gross Reductions	(74)	(74)
Change in Unrealized Gains/ (Losses)	(218)	(43)
Fair Value, Ending balance	14,955	15,356
Dividend, Interest, PIK and Other Income	888	979
Non-controlled Affiliated Investments | smarTours, LLC
Investments In And Advances To Affiliates [Line Items]
Gross Additions	23	4,382
Change in Unrealized Gains/ (Losses)	(23)	(48)
Fair Value, Ending balance		4,334
Dividend, Interest, PIK and Other Income	70	83
Non-controlled Affiliated Investments | Vivid Seats Ltd
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	1,021	944
Change in Unrealized Gains/ (Losses)	40	37
Fair Value, Ending balance	1,061	981
Non-controlled Affiliated Investments | WhiteHawk III Onshore Fund L.P.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	8,278	8,871
Gross Additions		848
Gross Reductions	(240)
Change in Unrealized Gains/ (Losses)	354	(84)
Fair Value, Ending balance	8,392	9,635
Dividend, Interest, PIK and Other Income	$ 287	$ 705