Borrowings - 2029 Notes (Details) $ in Thousands	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
Debt		2,775,533	2,151,713
2029 Notes
Borrowings
Total aggregate principal amount committed/ outstanding		204,000	204,000
Debt		204,000	204,000
Amount equal to net assets	$ 660,865
2029 Notes | Unsecured Debt
Borrowings
Minimum repayment of aggregate principal amount of senior notes	0.10
Debt Instrument, redemption price, percentage	100.00%
Net worth amount	$ 500,000
Percentage equal to net assets	65.00%
Asset coverage ratio	1.50
2029 Notes | Unsecured Debt | Below Investment Grade Event
Borrowings
Additional interest rate	1.00%
2029 Notes | Unsecured Debt | Secured Debt Ratio Event
Borrowings
Additional interest rate	1.50%
2029 Notes | Unsecured Debt | Below Investment Grade Event and a Secured Debt Ratio Event
Borrowings
Additional interest rate	2.00%
Series C Senior Unsecured Notes 2029 | Unsecured Debt
Borrowings
Total aggregate principal amount committed/ outstanding	$ 156,000
Interest rate	7.47%
Debt		$ 156,000	$ 156,000
Weighted average interest rate		7.50%	7.50%
Series D Senior Unsecured Notes 2029 | Unsecured Debt
Borrowings
Total aggregate principal amount committed/ outstanding	$ 48,000
Interest rate	7.47%
Debt		$ 48,000	$ 48,000
Weighted average interest rate		7.50%	7.50%