Fair Value and Maturity of Debt Outstanding - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Jun. 30, 2023
Debt Instrument [Line Items]
Asset coverage ratio	311.30%	297.00%
Outstanding amount	$ 2,505,497	$ 2,610,216
Asset coverage ratio on our senior security stock	185.10%	186.20%
Senior Notes
Debt Instrument [Line Items]
Outstanding amount	$ 2,505,497	$ 2,610,216