Debt - Schedule of Debt (Details) - USD ($)		Dec. 31, 2023	Dec. 31, 2022	Oct. 27, 2021	Mar. 28, 2016
Debt Instrument [Line Items]
Aggregate Principal Amount Committed		$ 1,181,600,000	$ 885,000,000
Drawn Amount	[1],[2]	851,921,000	659,836,000
Amount Available	[3]	329,679,000	225,164,000
SPV Asset Facility
Debt Instrument [Line Items]
Aggregate Principal Amount Committed		500,000,000	350,000,000		$ 500,000,000
Drawn Amount	[1],[2]	329,850,000	233,000,000
Amount Available	[3]	170,150,000	117,000,000
SMBC Corporate Revolving Facility
Debt Instrument [Line Items]
Aggregate Principal Amount Committed		385,000,000	350,000,000	$ 385,000,000
Drawn Amount	[1],[2]	225,471,000	241,836,000
Amount Available	[3]	159,529,000	108,164,000
Series 2020A Unsecured Notes
Debt Instrument [Line Items]
Aggregate Principal Amount Committed			50,000,000
Drawn Amount	[1],[2]		50,000,000
Series 2021A Unsecured Notes
Debt Instrument [Line Items]
Aggregate Principal Amount Committed	[4]	135,000,000	135,000,000
Drawn Amount	[1],[2],[4]	135,000,000	$ 135,000,000
FCRX Unsecured Notes
Debt Instrument [Line Items]
Aggregate Principal Amount Committed	[5]	111,600,000
Drawn Amount	[1],[2],[5]	111,600,000
Series 2023A Unsecured Notes
Debt Instrument [Line Items]
Aggregate Principal Amount Committed	[6]	50,000,000
Drawn Amount	[1],[2],[6]	$ 50,000,000

[1] As of December 31, 2023 and 2022, the carrying amount of the Company’s outstanding debt approximated fair value unless otherwise noted.

[2] The amount presented excludes netting of deferred financing costs.

[3] The amount available is subject to any limitations related to the respective debt facilities’ borrowing bases and foreign currency translation adjustments.

[4] As of December 31, 2023 and 2022, the fair value of the Series 2021A Unsecured Notes was approximately $128,296 and $123,223, respectively.

[5] As of December 31, 2023, the fair value of the FCRX Unsecured Notes was approximately $104,458.

[6] As of December 31, 2023, the fair value of the Series 2023A Unsecured Notes was approximately $51,986.