Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Insurance collateral deposits	$ 721	$ 714
Excess loss fund	622	617
Accumulated interest income	489	449
State collateral deposits	36	31
Materials and supplies	574	488
Debt issuance costs	292	0
Other	293	84
Total other assets	$ 3,027	$ 2,383