Agreements and Related Party Transactions - Summary of Investments in Controlled Affiliates (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2025		Dec. 31, 2024		Dec. 31, 2023
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance	[1],[2],[3]	$ 1,598,857
Net Realized Gains/ (Losses)		939		$ 2,108		$ (161,456)
Fair Value, Ending balance		1,569,418	[4],[5],[6]	1,598,857	[1],[2],[3]
Controlled Affiliated
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		48,051		63,919
Gross Additions		15,283		1,293
Gross Reductions		(5,914)		(8,673)
Net Realized Gains/ (Losses)		(3,800)		6,443
Change in Unrealized Gains/ (Losses)		6,731		(14,931)
Fair Value, Ending balance		60,351		48,051		63,919
Dividend, Interest, PIK and Other Income		7,681		10,869
Controlled Affiliated | Envocore LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		9,221		10,375
Gross Additions		1,829		1,615
Gross Reductions		(2,847)		(695)
Change in Unrealized Gains/ (Losses)		2,130		(2,074)
Fair Value, Ending balance		10,333		9,221		10,375
Dividend, Interest, PIK and Other Income		721		614
Controlled Affiliated | First Eagle Logan JV, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		32,575		39,004
Gross Reductions				(2,559)
Change in Unrealized Gains/ (Losses)		811		(3,870)
Fair Value, Ending balance		33,386		32,575		39,004
Dividend, Interest, PIK and Other Income		6,520		9,784
Controlled Affiliated | Loadmaster Derrick & Equipment, Inc.
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		3,476		6,287
Gross Reductions		(815)		(3,750)
Net Realized Gains/ (Losses)				6,443
Change in Unrealized Gains/ (Losses)		777		(5,504)
Fair Value, Ending balance		3,438		3,476		6,287
Dividend, Interest, PIK and Other Income		129		471
Controlled Affiliated | OEM Group, LLC
Investments In And Advances To Affiliates [Line Items]
Fair Value, Beginning balance		2,779		8,253
Gross Additions				(322)
Gross Reductions		(2,214)		(1,669)
Net Realized Gains/ (Losses)		(3,800)
Change in Unrealized Gains/ (Losses)		3,235		(3,483)
Fair Value, Ending balance				$ 2,779		$ 8,253
Dividend, Interest, PIK and Other Income		(1)
Controlled Affiliated | Slickdeals Holdings, LLC
Investments In And Advances To Affiliates [Line Items]
Gross Additions		13,454
Gross Reductions		(38)
Change in Unrealized Gains/ (Losses)		(222)
Fair Value, Ending balance		13,194
Dividend, Interest, PIK and Other Income		$ 312

[1] All debt investments are income-producing, unless otherwise noted. Equity and member interests are non-income-producing unless otherwise noted. The Company generally acquires its investments in private transactions exempt from registration under the Securities Act. Its investments are therefore generally subject to certain limitations on resale, and may be deemed to be “restricted securities” under the Securities Act.

[2] All positions held are non-controlled/non-affiliated investments, unless otherwise noted, as defined by the 1940 Act. Non-controlled/non-affiliated investments are investments that are neither controlled nor affiliated.

[3] The fair value of the investment was determined using significant unobservable inputs unless otherwise noted, as defined by the 1940 Act. See Note 2 “Summary of Significant Accounting Policies”.

[4] All debt investments are income-producing, unless otherwise noted. Equity and member interests are non-income-producing unless otherwise noted. The Company generally acquires its investments in private transactions exempt from registration under the Securities Act. Its investments are therefore generally subject to certain limitations on resale, and may be deemed to be “restricted securities” under the Securities Act.

[5] All positions held are non-controlled/non-affiliated investments, unless otherwise noted, as defined by the 1940 Act. Non-controlled/non-affiliated investments are investments that are neither controlled nor affiliated.

[6] The fair value of the investment was determined using significant unobservable inputs unless otherwise noted, as defined by the 1940 Act. See Note 2 “Summary of Significant Accounting Policies”.