Investments - ISLP Balance Sheet (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Investment Company, Nonconsolidated Subsidiary [Line Items]
Investments at fair value	$ 2,385,272	$ 2,386,977
Cash and cash equivalents	87,727	30,205
Foreign cash	4,612	29,575
Deferred financing costs	3,276	3,742
Interest receivable on investments	40,342	34,270
Forward currency exchange contracts (asset)	$ 55	$ 62
Derivative Asset, Type [Extensible Enumeration]	Foreign Exchange Forward	Foreign Exchange Forward
Total Assets	$ 2,675,388	$ 2,592,434
Debt	1,489,607	1,385,303
Payable for investments purchased	233	34,292
Interest payable on debt	15,897	12,130
Accounts payable and accrued expenses	4,906	2,954
Total Liabilities	1,549,609	1,476,043
Member's equity (deficit)	1,125,779	1,116,391
Total Liabilities and Total Net Assets	2,675,388	2,592,434
Investments, amortized cost	2,415,627	2,419,938
Foreign cash, cost	5,203	34,528
International Senior Loan Program, LLC
Investment Company, Nonconsolidated Subsidiary [Line Items]
Investments at fair value	686,583	707,683
Cash and cash equivalents	18,093	12,242
Foreign cash	29,581	10,279
Collateral on foreign currency exchange contracts	4,601	2,624
Capital contributions receivable		13,162
Deferred financing costs	2,320	2,759
Interest receivable on investments	9,547	7,617
Forward currency exchange contracts (asset)	48	1,053
Other receivable		59
Total Assets	750,773	757,478
Debt	350,691	375,260
Payable for investments purchased	13,015	10,456
Interest payable on debt	7,107	3,785
Interest payable on subordinated notes	17,157	13,118
Unrealized depreciation on forward currency exchange contracts	3,891	3,613
Dividend payable	2,296	2,195
Accounts payable and accrued expenses	273
Total Liabilities	657,428	670,449
Member's equity (deficit)	93,345	87,029
Total Liabilities and Total Net Assets	750,773	757,478
Investments, amortized cost	705,448	745,570
Foreign cash, cost	29,131	10,274
Accumulated amortization	1,589	1,150
International Senior Loan Program, LLC | Related Party
Investment Company, Nonconsolidated Subsidiary [Line Items]
Subordinated notes payable to members	$ 262,998	$ 262,022