Summary of Significant Accounting Policies - Other Noncurrent Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Accounting Policies [Abstract]
Deferred financing costs, net	$ 1,353	$ 1,867
Prepayments to outside operators	707	284
Right of use assets	309	700
Other deposits	50	98
Total other non-current assets, net	$ 2,419	$ 2,949