Borrowings - July 2028 Notes (Details) $ in Thousands	Jul. 10, 2025 USD ($)	Oct. 20, 2023 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Borrowings
Total aggregate principal amount committed/ outstanding			$ 3,780,439	$ 2,656,207
Debt			2,775,533	2,151,713
Interest expense - Revolving Credit Facility | Revolving Credit Agreement
Borrowings
Debt			$ 256,500	$ 396,100
Amount equal to net assets		$ 1,063,400
Percentage equal to net assets		65.00%
Weighted average interest rate			6.20%	7.00%
Unsecured Debt | 2028 Note Purchase Agreement
Borrowings
Total aggregate principal amount committed/ outstanding	$ 42,000		$ 42,000
Minimum repayment of aggregate principal amount of senior notes	0.10
Debt Instrument, redemption price, percentage	100.00%
Net worth amount	$ 500,000
Amount equal to net assets	$ 1,063,400
Percentage equal to net assets	65.00%
Asset coverage ratio	1.50
Weighted average interest rate	6.20%
Unsecured Debt | Below Investment Grade Event | 2028 Note Purchase Agreement
Borrowings
Additional interest rate	1.00%
Unsecured Debt | Secured Debt Ratio Event | 2028 Note Purchase Agreement
Borrowings
Additional interest rate	1.50%
Unsecured Debt | Below Investment Grade Event and a Secured Debt Ratio Event | 2028 Note Purchase Agreement
Borrowings
Additional interest rate	2.00%