Leases - Summary of Supplemental Cash Flow Information for Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases	$ 20,704	$ 17,436	$ 11,905
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 27,128	$ 48,310	$ 25,555