Summary of Significant Accounting Policies - Other Non-current Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
Accounting Policies [Abstract]
Deferred financing costs, net	$ 1,345	$ 1,353
Prepayments to outside operators	690	707
Right of use assets	208	309
Other deposits	50	50
Total other non-current assets, net	$ 2,293	$ 2,419