Investments - Summary of Investments at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2023		Dec. 31, 2022	Dec. 31, 2021
Summary Of Investment Holdings [Line Items]
Cost	$ 1,603,588	[1],[2],[3]	$ 1,291,456
Fair Value	1,566,045	[1],[2],[3]	1,262,956	$ 1,262,956
Unrealized Appreciation/ (Depreciation)	(37,543)		(28,500)
Senior Secured First Lien
Summary Of Investment Holdings [Line Items]
Cost	460,037		312,345
Fair Value	445,475		301,001
Unrealized Appreciation/ (Depreciation)	(14,562)		(11,344)
Unitranche First Lien
Summary Of Investment Holdings [Line Items]
Cost	955,484		842,867
Fair Value	933,801		824,107
Unrealized Appreciation/ (Depreciation)	(21,683)		(18,760)
Unitranche First Lien Last Out
Summary Of Investment Holdings [Line Items]
Cost	15,309		14,879
Fair Value	13,946		13,827
Unrealized Appreciation/ (Depreciation)	(1,363)		(1,052)
Senior Secured Second Lien
Summary Of Investment Holdings [Line Items]
Cost	67,392		67,001
Fair Value	62,300		60,877
Unrealized Appreciation/ (Depreciation)	(5,092)		(6,124)
Unsecured Debt One
Summary Of Investment Holdings [Line Items]
Cost	5,368		4,984
Fair Value	4,926		4,533
Unrealized Appreciation/ (Depreciation)	(442)		(451)
Equity & Other
Summary Of Investment Holdings [Line Items]
Cost	39,007		35,993
Fair Value	49,235		44,851
Unrealized Appreciation/ (Depreciation)	10,228		8,858
LLC/LP Equity Interests
Summary Of Investment Holdings [Line Items]
Cost	60,991		13,387
Fair Value	56,362		13,760
Unrealized Appreciation/ (Depreciation)	$ (4,629)		$ 373

[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”.