Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 60	$ 10
Cash paid for federal and state income taxes	811	381
Non-cash transactions:
Change in accounts payable related to property and equipment additions	(84)	0
Property and equipment acquired under capital leases	$ 1,208	$ 1,808