Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 65	$ 19
Cash paid for federal and state income taxes	5	52
Non-cash transactions:
Change in accounts payable related to property and equipment additions	(683)	(39)
Property and equipment acquired under finance leases	$ 556	$ 0