Financial Highlights - Summary of Information about Senior Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jul. 27, 2022	Oct. 27, 2021	Jan. 09, 2020
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Convertible Notes	$ 48,118,000	$ 47,485,000
Total	620,000,000.0	466,000,000.0
2025 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Total				$ 182,500,000
Credit Suisse Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility		10,000,000				$ 190,000,000.0
KeyBank Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	187,500,000	81,000,000			$ 350,000,000.0
Senior Securities
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Total	620,000,000	466,000,000	$ 310,000,000
Asset Coverage per Unit	1,741	1,958	1,770
Senior Securities | 2025 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Notes	182,500,000	125,000,000	125,000,000
Asset Coverage per Unit	1,741	1,958	1,770
Average Market Value per Unit	1,005,960
Senior Securities | Convertible Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Convertible Notes	50,000,000	50,000,000	50,000,000
Asset Coverage per Unit	1,741	1,958	1,770
Senior Securities | August 2026 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Notes	125,000,000	125,000,000
Asset Coverage per Unit	1,741	1,958
Senior Securities | December 2026 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Notes	75,000,000	75,000,000
Asset Coverage per Unit	1,741	1,958
Senior Securities | Credit Suisse Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility		10,000,000	135,000,000
Asset Coverage per Unit		1,958	$ 1,770
Senior Securities | KeyBank Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	187,500,000	81,000,000
Asset Coverage per Unit	$ 1,741	$ 1,958