Leases - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2014 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2022 USD ($) extensionOption	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2018	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease payments			$ 72,300	$ 61,900
Initial term of lease (in years)			10 years
Estimated minimum future rental payments			$ 286,173
Impairment charges					$ 5,000
Operating lease right of use asset non cash			69,400	69,400
Operating lease liability non cash			$ 62,800	$ 62,800
Corporate Office Lease, Two Five-Year Extension Options
Lessee, Lease, Description [Line Items]
Initial term of lease (in years)	13 years
Annual rent at lease inception	$ 2,500
Annual rent in the terminal year of lease	$ 3,900
Number of extension options | extensionOption			2
Renewable term of lease (in years)			5 years
Estimated minimum future rental payments			$ 24,400
Estimated future minimum sublease payments							$ 12,200	$ 12,200
Initial leased premises surrendered						15.00%
Regional Offices Sublease
Lessee, Lease, Description [Line Items]
Estimated future minimum sublease payments		$ 2,900
Sublease term (in years)		9 years