Leases - Components of Lease Expense and Supplemental Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Leases [Abstract]
Operating lease costs	$ 15,637	$ 16,182
Variable lease costs	$ 7,724	$ 6,194
Weighted-average remaining lease term (in years) - operating leases	15 years 2 months 15 days	15 years 4 months 13 days
Weighted-average discount rate - operating leases	6.52%	6.54%