Borrowings - July 2030 Notes (Details) $ in Thousands	Jul. 10, 2025 USD ($)	Jul. 24, 2024 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Borrowings
Total aggregate principal amount committed/ outstanding			$ 3,780,439	$ 2,656,207
2029 Notes
Borrowings
Total aggregate principal amount committed/ outstanding			$ 204,000	$ 204,000
Amount equal to net assets		$ 660,865
Secured Debt | Series F Senior Unsecured Notes July 2030
Borrowings
Total aggregate principal amount committed/ outstanding	$ 161,000
Interest rate	6.57%
Asset coverage ratio	1.50
Secured Debt | 2029 Notes
Borrowings
Minimum repayment of aggregate principal amount of senior notes		0.10
Debt Instrument, redemption price, percentage		100.00%
Secured Debt | Below Investment Grade Event | Series F Senior Unsecured Notes July 2030
Borrowings
Additional interest rate	1.00%
Secured Debt | Secured Debt Ratio Event | Series F Senior Unsecured Notes July 2030
Borrowings
Additional interest rate	1.50%
Secured Debt | Below Investment Grade Event and a Secured Debt Ratio Event | Series F Senior Unsecured Notes July 2030
Borrowings
Additional interest rate	2.00%
Secured Debt | Interest expense - Revolving Credit Facility | 2028 Note Purchase Agreement
Borrowings
Net worth amount	$ 500,000
Percentage equal to net assets	65.00%