Fair Value Measurement - Summary of Changes in Fair Value of Level 3 Assets By Investment Type (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		$ (12,460)	$ (15,513)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Gain (Loss) on Investments	Gain (Loss) on Investments
1st Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		$ (7,715)	$ (14,587)
1st Lien/Last-Out Unitranche
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		767	(1,336)
2nd Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		1,999	(2,808)
Unsecured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		(8,010)	(78)
Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		582	2,510
Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		(86)	1,160
Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Change in Unrealized Appreciation (Depreciation) for assets still held		3	(374)
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		3,343,635	3,341,847
Purchases	[1]	213,732	51,334
Net Realized Gain (Loss)		(16,988)	(36,261)
Net Change in Unrealized Appreciation (Depreciation)		(2,859)	22,088
Sales and Settlements	[2]	(173,906)	(30,140)
Net Amortization of Premium/Discount		6,053	5,082
Transfers In	[3]	35,222
Transfers Out	[3]	(27,821)	(34,201)
Ending Balance		3,377,068	3,319,749
Level 3 | 1st Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		3,036,965	3,050,929
Purchases	[1]	194,044	49,657
Net Realized Gain (Loss)		(17,646)	5
Net Change in Unrealized Appreciation (Depreciation)		3,536	(13,252)
Sales and Settlements	[2]	(129,587)	(30,037)
Net Amortization of Premium/Discount		5,103	4,541
Transfers In	[3]	35,222
Transfers Out	[3]	(27,821)	(34,201)
Ending Balance		3,099,816	3,027,642
Level 3 | 1st Lien/Last-Out Unitranche
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		144,743	116,230
Purchases	[1]	12,908	588
Net Change in Unrealized Appreciation (Depreciation)		767	(1,336)
Sales and Settlements	[2]	(103)	(103)
Net Amortization of Premium/Discount		199	305
Ending Balance		158,514	115,684
Level 3 | 2nd Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		66,562	89,573
Purchases	[1]	5,060	491
Net Realized Gain (Loss)			(35,383)
Net Change in Unrealized Appreciation (Depreciation)		1,042	32,575
Sales and Settlements	[2]	(40,129)
Net Amortization of Premium/Discount		1,101	233
Ending Balance		33,636	87,489
Level 3 | Unsecured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		27,314	7,630
Purchases	[1]	1,596	598
Net Change in Unrealized Appreciation (Depreciation)		(8,010)	(78)
Net Amortization of Premium/Discount		(350)	3
Ending Balance		20,550	8,153
Level 3 | Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		37,296	42,377
Purchases		124
Net Change in Unrealized Appreciation (Depreciation)		582	2,510
Ending Balance		38,002	44,887
Level 3 | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		30,511	34,497
Net Realized Gain (Loss)		658	(883)
Net Change in Unrealized Appreciation (Depreciation)		(779)	2,043
Sales and Settlements	[2]	(4,087)
Ending Balance		26,303	35,657
Level 3 | Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance		244	611
Net Change in Unrealized Appreciation (Depreciation)		3	(374)
Ending Balance		$ 247	$ 237

[1] Purchases may include PIK, securities received in corporate actions and restructurings.

[2] Sales and Settlements may include securities delivered in corporate actions and restructuring of investments.

[3] Transfers in (out) of Level 3 are due to a decrease (increase) in the quantity and reliability of broker quotes obtained by the Investment Adviser.