Leases - Schedule of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Operating lease cost:
Operating lease cost	$ 79,184	$ 74,086	$ 67,414
Variable lease cost	17,732	16,315	15,229
Total operating lease cost	96,916	90,401	82,643
Financing lease cost:
Amortization of financing lease assets	568	327	3
Interest on financing lease liabilities	215	145	1
Total financing lease cost	783	472	4
Total lease cost	97,699	90,873	82,647
Sublease rental income	$ 3,100	$ 3,700	$ 3,600
Weighted-average remaining lease term (years):
Operating leases	4 years 9 months 21 days	4 years 11 months 19 days
Financing leases	2 years 9 months 7 days	3 years 8 months 1 day
Weighted-average discount rate:
Operating leases	8.30%	8.51%
Financing leases	11.14%	11.14%