Leases - Summary of Supplemental Cash Flow Information for Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases	$ 17,652	$ 17,168	$ 20,704
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 7,801	$ 20,330	$ 27,128