Borrowings - 2029 Notes (Details) $ in Thousands	Jul. 24, 2024 USD ($)	Oct. 20, 2023 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)
Borrowings
Total aggregate principal amount committed/ outstanding			$ 2,394,963	$ 1,587,138
Debt			1,885,869	1,247,946
Net assets			1,879,965	1,302,667	$ 1,131,752
Interest expense - Revolving Credit Facility | Revolving Credit Agreement
Borrowings
Debt			188,000	$ 240,800
Net assets	$ 500,000	$ 500,000
Amount equal to net assets	$ 660,865	$ 660,865
Percentage equal to net assets	65.00%	65.00%
Series C Senior Unsecured Notes 2029 | Private Placement Bonds
Borrowings
Total aggregate principal amount committed/ outstanding	$ 156,000
Interest rate	7.47%
Debt			$ 156,000
Weighted average interest rate			7.47%
Series D Senior Unsecured Notes 2029 | Private Placement Bonds
Borrowings
Total aggregate principal amount committed/ outstanding	$ 48,000
Interest rate	7.47%
Debt			$ 48,000
Weighted average interest rate			7.47%
2029 Notes | Private Placement Bonds
Borrowings
Minimum repayment of aggregate principal amount of senior notes	0.10
Debt Instrument, redemption price, percentage	100.00%
Asset coverage ratio	1.50
2029 Notes | Private Placement Bonds | Below Investment Grade Event
Borrowings
Additional interest rate	1.00%
2029 Notes | Private Placement Bonds | Secured Debt Ratio Event
Borrowings
Additional interest rate	1.50%
2029 Notes | Private Placement Bonds | Below Investment Grade Event and a Secured Debt Ratio Event
Borrowings
Additional interest rate	2.00%