Agreements and Related Party Transactions - Summary of Investments in Non-controlled Affiliates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	$ 1,262,956
Net Realized Gains/ (Losses)	(161,456)	$ (5,482)	$ (16,849)
Fair Value, Ending balance	1,582,075	1,262,956
Non-controlled Affiliated Investments
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	43,080	51,701
Gross Additions	16,819	18,631
Gross Reductions	(2,775)	(24,932)
Net Realized Gains/ (Losses)		7,098
Change in Unrealized Gains/ (Losses)	(4,505)	(9,418)
Fair Value, Ending balance	52,619	43,080	51,701
Dividend, Interest, PIK and Other Income	6,157	8,900
Non-controlled Affiliated Investments | AX VI INV2 Holding AB
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	12,117
Gross Additions	1,596	11,436
Change in Unrealized Gains/ (Losses)	439	681
Fair Value, Ending balance	14,152	12,117
Dividend, Interest, PIK and Other Income	1,299	321
Non-controlled Affiliated Investments | ASP MCS Acquisition Corp.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	826	1,616
Gross Additions	226	263
Gross Reductions	(3)	(3)
Change in Unrealized Gains/ (Losses)	(250)	(1,050)
Fair Value, Ending balance	799	826	1,616
Dividend, Interest, PIK and Other Income	37	28
Non-controlled Affiliated Investments | Bayside Opco, LLC
Investments In And Advances To Affiliates [Line Items]
Gross Additions	6,615
Gross Reductions	(262)
Change in Unrealized Gains/ (Losses)	351
Fair Value, Ending balance	6,704
Dividend, Interest, PIK and Other Income	437
Non-controlled Affiliated Investments | Battery Solutions, Inc.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		7,031
Gross Additions		2,129
Gross Reductions		(14,712)
Net Realized Gains/ (Losses)		7,098
Change in Unrealized Gains/ (Losses)		(1,546)
Fair Value, Ending balance			7,031
Dividend, Interest, PIK and Other Income		2,113
Non-controlled Affiliated Investments | GACP II LP
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	4,889	12,619
Gross Reductions	(1,091)	(7,804)
Change in Unrealized Gains/ (Losses)	129	74
Fair Value, Ending balance	3,927	4,889	12,619
Dividend, Interest, PIK and Other Income	672	1,593
Non-controlled Affiliated Investments | Isagenix International, LLC
Investments In And Advances To Affiliates [Line Items]
Gross Additions	2,642
Change in Unrealized Gains/ (Losses)	(96)
Fair Value, Ending balance	2,546
Dividend, Interest, PIK and Other Income	413
Non-controlled Affiliated Investments | Slickdeals Holdings, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	15,433	15,847
Gross Additions	88	93
Gross Reductions	(148)	(148)
Change in Unrealized Gains/ (Losses)	(181)	(359)
Fair Value, Ending balance	15,192	15,433	15,847
Dividend, Interest, PIK and Other Income	1,866	1,268
Non-controlled Affiliated Investments | smarTours, LLC
Investments In And Advances To Affiliates [Line Items]
Gross Additions	4,805
Change in Unrealized Gains/ (Losses)	(4,805)
Dividend, Interest, PIK and Other Income	47
Non-controlled Affiliated Investments | Southern Technical Institute, Inc.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		7,686
Change in Unrealized Gains/ (Losses)		(7,686)
Fair Value, Ending balance			7,686
Dividend, Interest, PIK and Other Income		2,932
Non-controlled Affiliated Investments | Vivid Seats Ltd
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	944	922
Change in Unrealized Gains/ (Losses)	77	22
Fair Value, Ending balance	1,021	944	922
Non-controlled Affiliated Investments | WhiteHawk III Onshore Fund L.P.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	8,871	5,980
Gross Additions	847	4,710
Gross Reductions	(1,271)	(2,265)
Change in Unrealized Gains/ (Losses)	(169)	446
Fair Value, Ending balance	8,278	8,871	$ 5,980
Dividend, Interest, PIK and Other Income	$ 1,386	$ 645