Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 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	459	449
State collateral deposits	42	31
Materials and supplies	460	488
Other	190	84
Total other assets	$ 2,482	$ 2,383