Other Current Assets and Other Assets - Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Non-trade receivables	$ 6,270	$ 6,063
Prepaid maintenance	5,293	2,942
Prepaid insurance	978	266
Other prepaid assets	4,355	3,086
Total other current assets	$ 16,896	$ 12,357