Fair Value of Financial Instruments - Summary of Reconciliation of Investments that Use Level 3 Inputs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 1,167,987	$ 1,105,680
Amortized discounts/premiums	1,748	1,382
Paid in-kind interest	852	2,482
Net realized gain (loss)	$ 181	$ 8,286
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain Loss On Investments	Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	$ (4,135)	$ (3,445)
Purchases	312,778	59,536
Sales/return of capital/principal repayments/paydowns	(50,467)	(36,637)
Transfers in	28,060	13,965
Transfers out	(6,210)	(1,327)
Ending balance	1,450,794	1,149,922
Net change in unrealized appreciation (depreciation) from investments still held	(4,193)	(1,048)
Senior Secured First Lien
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	277,786	268,851
Amortized discounts/premiums	422	302
Paid in-kind interest	167	152
Net realized gain (loss)	$ 180	$ 3
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain Loss On Investments	Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	$ (3,497)	$ 614
Purchases	193,362	9,438
Sales/return of capital/principal repayments/paydowns	(42,401)	(10,389)
Ending balance	426,019	268,971
Net change in unrealized appreciation (depreciation) from investments still held	(3,555)	624
Unitranche First Lien
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	771,348	711,296
Amortized discounts/premiums	1,234	868
Paid in-kind interest	104
Net realized gain (loss)	$ 1	$ (5)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain Loss On Investments	Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	$ (2,994)	$ 266
Purchases	116,424	50,098
Sales/return of capital/principal repayments/paydowns	(8,066)	(3,682)
Transfers in	28,060
Ending balance	906,111	758,841
Net change in unrealized appreciation (depreciation) from investments still held	(2,994)	160
Unitranche First Last Out
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	13,827	13,723
Amortized discounts/premiums	3	2
Paid in-kind interest	161
Net change in unrealized appreciation (depreciation)	(311)	217
Purchases	266
Sales/return of capital/principal repayments/paydowns		(2,298)
Ending balance	13,946	11,644
Net change in unrealized appreciation (depreciation) from investments still held	(311)	217
Senior Secured Second Lien
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	56,586	47,584
Amortized discounts/premiums	87	131
Paid in-kind interest	241	$ 174
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	1,158	$ (1,318)
Purchases	51
Sales/return of capital/principal repayments/paydowns		(4,306)
Transfers in		13,965
Transfers out	(6,210)
Ending balance	51,913	56,230
Net change in unrealized appreciation (depreciation) from investments still held	1,158	(1,266)
Unsecured Debt
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	4,533	5,620
Amortized discounts/premiums	2	79
Paid in-kind interest	179	$ 158
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	9	$ 24
Purchases	203
Sales/return of capital/principal repayments/paydowns		(1,932)
Ending balance	4,926	3,949
Net change in unrealized appreciation (depreciation) from investments still held	9	(15)
Equity & Other
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 43,907	58,606
Paid in-kind interest		1,998
Net realized gain (loss)		$ 8,288
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain Loss On Investments	Gain Loss On Investments
Net change in unrealized appreciation (depreciation)	$ 1,500	$ (3,248)
Purchases	2,472
Sales/return of capital/principal repayments/paydowns		(14,030)
Transfers out		(1,327)
Ending balance	47,879	50,287
Net change in unrealized appreciation (depreciation) from investments still held	$ 1,500	$ (768)