Financial Highlights - Summary of Information about Senior Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Oct. 27, 2021
KeyBank Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	$ 483,000	$ 113,000					$ 600,000
Senior Securities
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	1,061,331	888,000	$ 645,500	$ 620,000	$ 466,000	$ 310,000
Asset Coverage per Unit	1,870	1,927	1,947	1,741	1,958	1,770
Senior Securities \| 2025 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility		152,500	182,500	182,500	125,000	125,000
Asset Coverage per Unit		1,927	1,947	1,741	1,958	1,770
Average Market Value per Unit		1,009	1,006	1,006
Senior Securities \| Convertible Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility		50,000	50,000	50,000	50,000	50,000
Asset Coverage per Unit		1,927	1,947	1,741	1,958	1,770
Senior Securities \| August 2026 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	125,000	125,000	125,000	125,000	125,000
Asset Coverage per Unit	1,870	1,927	1,947	1,741	1,958
Senior Securities \| December 2026 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	75,000	75,000	75,000	75,000	75,000
Asset Coverage per Unit	1,870	1,927	1,947	1,741	1,958
Senior Securities \| March 2029 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	116,637	115,000
Asset Coverage per Unit	1,870	1,927
Average Market Value per Unit	1,010	1,012
Senior Securities \| September 2029 Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	119,194	115,000
Asset Coverage per Unit	1,870	1,927
Average Market Value per Unit	1,012	1,014
Senior Securities \| Series A Notes
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility	142,500	142,500
Asset Coverage per Unit	1,870	1,927
Senior Securities \| Credit Suisse Credit Facility
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Credit facility					10,000	135,000
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	483,000	113,000	213,000	187,500	81,000
Asset Coverage per Unit	$ 1,870	$ 1,927	$ 1,947	$ 1,741	$ 1,958