Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 424	$ 218
Cash paid for federal and state income taxes	258	182
Cash refund for NOL carryback under CARES Act	3,712	2,703
Non-cash transactions:
Change in accounts payable related to property and equipment additions	(1,238)	(1,237)
Property and equipment acquired under finance leases	$ 2,083	$ 1,656