Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 424	$ 60
Cash paid for federal and state income taxes	234	811
Non-cash transactions:
Change in accounts payable related to property and equipment additions	(1,538)	(84)
Property and equipment acquired under finance leases	4,148	1,208
Issuance of common shares in asset acquisition (see Note 6)	$ 392	$ 0