Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Insurance collateral deposits	$ 714	$ 714
Excess loss fund	617	617
Accumulated interest income	469	449
State collateral deposits	36	31
Materials and supplies	509	488
Debt issuance costs	324	0
Other	261	84
Total other assets	$ 2,930	$ 2,383