Leases - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating lease cost:
Operating lease cost	$ 67,414	$ 61,980
Variable lease cost	15,229	13,000
Total operating lease cost	82,643	74,980
Financing lease cost:
Amortization of financing lease assets	3	0
Interest on financing lease liabilities	1	0
Total financing lease cost	4	0
Total lease cost	82,647	74,980
Sublease rental income	$ 3,600	$ 3,400
Weighted-average remaining lease term (years):
Weighted-average remaining lease term, Operating leases (in years)	5 years 1 month 13 days	5 years 29 days
Weighted-average remaining lease term, Financing leases (in years)	4 years 1 month 6 days
Weighted-average discount rate:
Weighted-average discount rate, Operating leases (as percentage)	8.32%	5.92%
Weighted-average discount rate, Financing leases (as percentage)	11.14%	0.00%