Derivatives - Narrative (Details) - Interest rate swaps - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Apr. 11, 2024	Feb. 01, 2024	Dec. 05, 2023
Open Forward Foreign Currency Contract [Line Items]
Net (gain)/loss related to the fair value hedge	$ (5,763)	$ (2,991)
2028 Notes
Open Forward Foreign Currency Contract [Line Items]
Fixed interest rate (as a percent)			7.31%		7.31%
Notional amount			$ 225,000		$ 225,000
Net (gain)/loss related to the fair value hedge	3,906	(279)
2028 Notes | Tranche one
Open Forward Foreign Currency Contract [Line Items]
Fixed interest rate (as a percent)					7.31%
Notional amount					$ 225
2028 Notes | Tranche two
Open Forward Foreign Currency Contract [Line Items]
Fixed interest rate (as a percent)					7.31%
Notional amount					$ 225,000
2028 Notes | One-month Secured Overnight Financing Rate (SOFR)
Open Forward Foreign Currency Contract [Line Items]
Basis spread on variable rate (as a percent)			2.835%		3.327%
2028 Notes | One-month Secured Overnight Financing Rate (SOFR) | Tranche one
Open Forward Foreign Currency Contract [Line Items]
Basis spread on variable rate (as a percent)					3.327%
2028 Notes | One-month Secured Overnight Financing Rate (SOFR) | Tranche two
Open Forward Foreign Currency Contract [Line Items]
Basis spread on variable rate (as a percent)					2.835%
2029 Notes
Open Forward Foreign Currency Contract [Line Items]
Fixed interest rate (as a percent)				6.248%
Notional amount				$ 600,000
Net (gain)/loss related to the fair value hedge	$ (1,857)	$ (3,270)
2029 Notes | One-month Secured Overnight Financing Rate (SOFR)
Open Forward Foreign Currency Contract [Line Items]
Basis spread on variable rate (as a percent)				2.444%