Commitments and Contingencies - Summary of Unfunded Debt and Equity Commitments (Details) - USD ($) $ in Thousands		Mar. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Other Commitment		$ 336,319	$ 323,663
Unfunded Debt and Equity Commitments [Member]
Other Commitments [Line Items]
Other Commitment		336,319	323,663
Unfunded Debt and Equity Commitments [Member] | SLR Credit Solutions [Member]
Other Commitments [Line Items]
Other Commitment	[1]	44,263	44,263
Unfunded Debt and Equity Commitments [Member] | Outset Medical, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		35,084	35,084
Unfunded Debt and Equity Commitments [Member] | Apeel Technology, Inc [Member]
Other Commitments [Line Items]
Other Commitment		32,786	32,786
Unfunded Debt and Equity Commitments [Member] | CC SAG Holdings Corp. (Spectrum Automotive) [Member]
Other Commitments [Line Items]
Other Commitment		20,670	20,670
Unfunded Debt and Equity Commitments [Member] | Human Interest, Inc [Member]
Other Commitments [Line Items]
Other Commitment		20,104	20,104
Unfunded Debt and Equity Commitments [Member] | Glooko, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		17,868	17,868
Unfunded Debt and Equity Commitments [Member] | World Insurance Associates, LLC [Member]
Other Commitments [Line Items]
Other Commitment		9,190	17,117
Unfunded Debt and Equity Commitments [Member] | iCIMS, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		10,360	11,435
Unfunded Debt and Equity Commitments [Member] | Spectrum Pharmaceuticals, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		8,771	8,771
Unfunded Debt and Equity Commitments [Member] | Arcutis Biotherapeutics, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		8,356	8,356
Unfunded Debt and Equity Commitments [Member] | Atria Wealth Solutions, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		8,215	8,215
Unfunded Debt and Equity Commitments [Member] | Ardelyx, Inc [Member]
Other Commitments [Line Items]
Other Commitment		7,752	7,752
Unfunded Debt and Equity Commitments [Member] | Luxury Asset Capital, LLC [Member]
Other Commitments [Line Items]
Other Commitment		7,500	7,500
Unfunded Debt and Equity Commitments [Member] | Cerapedics, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		6,735	6,735
Unfunded Debt and Equity Commitments [Member] | RSC Acquisition, Inc [Member]
Other Commitments [Line Items]
Other Commitment		5,002	7,498
Unfunded Debt and Equity Commitments [Member] | Maurices, Incorporated [Member]
Other Commitments [Line Items]
Other Commitment		2,745	4,314
Unfunded Debt and Equity Commitments [Member] | Kaseya, Inc [Member]
Other Commitments [Line Items]
Other Commitment		3,807	3,936
Unfunded Debt and Equity Commitments [Member] | Vessco Midco Holdings, LLC [Member]
Other Commitments [Line Items]
Other Commitment		3,455	3,892
Unfunded Debt and Equity Commitments [Member] | Copper River Seafoods, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		7,857	3,595
Unfunded Debt and Equity Commitments [Member] | BDG Media, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		10,224	3,546
Unfunded Debt and Equity Commitments [Member] | Meditrina, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		3,367	3,367
Unfunded Debt and Equity Commitments [Member] | One Touch Direct, LLC [Member]
Other Commitments [Line Items]
Other Commitment		3,185	3,069
Unfunded Debt and Equity Commitments [Member] | DeepIntent, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		3,118	3,049
Unfunded Debt and Equity Commitments [Member] | Foundation Consumer Brands, LLC [Member]
Other Commitments [Line Items]
Other Commitment		3,009	3,009
Unfunded Debt and Equity Commitments [Member] | SCP Eye Care, LLC [Member]
Other Commitments [Line Items]
Other Commitment		2,388	2,771
Unfunded Debt and Equity Commitments [Member] | Basic Fun, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		2,687	2,675
Unfunded Debt and Equity Commitments [Member] | Kid Distro Holdings, LLC [Member]
Other Commitments [Line Items]
Other Commitment		2,650	2,650
Unfunded Debt and Equity Commitments [Member] | Plastics Management, LLC [Member]
Other Commitments [Line Items]
Other Commitment		0	2,424
Unfunded Debt and Equity Commitments [Member] | Southern Orthodontic Partners Management, LLC [Member]
Other Commitments [Line Items]
Other Commitment		1,586	1,918
Unfunded Debt and Equity Commitments [Member] | Pediatric Home Respiratory Services, LLC [Member]
Other Commitments [Line Items]
Other Commitment		1,805	1,805
Unfunded Debt and Equity Commitments [Member] | Pinnacle Treatment Centers, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		960	1,745
Unfunded Debt and Equity Commitments [Member] | Ultimate Baked Goods Midco LLC [Member]
Other Commitments [Line Items]
Other Commitment		2,224	1,636
Unfunded Debt and Equity Commitments [Member] | Orthopedic Care Partners Management, LLC [Member]
Other Commitments [Line Items]
Other Commitment		971	1,620
Unfunded Debt and Equity Commitments [Member] | Ivy Fertility Services, LLC [Member]
Other Commitments [Line Items]
Other Commitment		0	1,571
Unfunded Debt and Equity Commitments [Member] | Composite Technology Acquisition Corp [Member]
Other Commitments [Line Items]
Other Commitment		970	1,537
Unfunded Debt and Equity Commitments [Member] | NAC Holdings Corporation [Member]
Other Commitments [Line Items]
Other Commitment		0	1,479
Unfunded Debt and Equity Commitments [Member] | SLR Healthcare ABL [Member]
Other Commitments [Line Items]
Other Commitment		1,400	1,400
Unfunded Debt and Equity Commitments [Member] | SPAR Marketing Force, Inc. [Member]
Other Commitments [Line Items]
Other Commitment		2,551	1,338
Unfunded Debt and Equity Commitments [Member] | RxSense Holdings LLC [Member]
Other Commitments [Line Items]
Other Commitment		1,250	1,250
Unfunded Debt and Equity Commitments [Member] | Erie Construction Mid-west, LLC [Member]
Other Commitments [Line Items]
Other Commitment		1,248	1,248
Unfunded Debt and Equity Commitments [Member] | Peter C. Foy & Associates Insurance Services, LLC [Member]
Other Commitments [Line Items]
Other Commitment		0	1,094
Unfunded Debt and Equity Commitments [Member] | American Teleconferencing Services, Ltd. [Member]
Other Commitments [Line Items]
Other Commitment		1,137	1,090
Unfunded Debt and Equity Commitments [Member] | Enverus Holdings, Inc [Member]
Other Commitments [Line Items]
Other Commitment		1,004	1,004
Unfunded Debt and Equity Commitments [Member] | Montefiore Nyack Hospital [Member]
Other Commitments [Line Items]
Other Commitment		1,400	1,034
Unfunded Debt and Equity Commitments [Member] | SunMed Group Holdings, LLC [Member]
Other Commitments [Line Items]
Other Commitment		908	843
Unfunded Debt and Equity Commitments [Member] | SLR Equipment Finance [Member]
Other Commitments [Line Items]
Other Commitment		3,500	1,000
Unfunded Debt and Equity Commitments [Member] | GSM Acquisition Corp [Member]
Other Commitments [Line Items]
Other Commitment		862	784
Unfunded Debt and Equity Commitments [Member] | Tilley Distribution, Inc [Member]
Other Commitments [Line Items]
Other Commitment		635	525
Unfunded Debt and Equity Commitments [Member] | BayMark Health Services, Inc [Member]
Other Commitments [Line Items]
Other Commitment		0	391
Unfunded Debt and Equity Commitments [Member] | High Street Buyer, Inc [Member]
Other Commitments [Line Items]
Other Commitment		327	327
Unfunded Debt and Equity Commitments [Member] | ENS Holdings III Corp, LLC [Member]
Other Commitments [Line Items]
Other Commitment		317	144
Unfunded Debt and Equity Commitments [Member] | All State Ag Parts, LLC
Other Commitments [Line Items]
Other Commitment		6	135
Unfunded Debt and Equity Commitments [Member] | TAUC Management, LLC [Member]
Other Commitments [Line Items]
Other Commitment		294	294
Unfunded Debt and Equity Commitments [Member] | ONS MSO, LLC [Member]
Other Commitments [Line Items]
Other Commitment		10,961	0
Unfunded Debt and Equity Commitments [Member] | United Digestive MSO Parent, LLC [Member]
Other Commitments [Line Items]
Other Commitment		5,259	0
Unfunded Debt and Equity Commitments [Member] | Urology Management Holdings, Inc [Member]
Other Commitments [Line Items]
Other Commitment		$ 3,596	$ 0

[1] The Company controls the funding of the SLR Credit Solutions and SLR Healthcare ABL commitments and may cancel them at its discretion.