Commitments and Contingencies - Additional Lease Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term (years)	11 years 10 months 24 days	14 years 4 months 24 days
Weighted average discount rate	6.10%	6.10%
Operating cash outflows from operating leases	$ 1,975	$ 1,592
Right-of-use assets obtained in exchange for operating lease liabilities	$ 10,358	$ 10,791