Segment Information - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Sales to external customers	$ 27,745	$ 25,288
Operating income (loss)	1,192	955
Interest expense, net	269	184
Other expense, net	(9)	(38)
Consolidated income before income taxes	938	809
Assets	100,204		$ 92,066
United States
Sales to external customers	24,475	22,526
Operating income (loss)	1,108	945
Assets	91,891		84,104
Canada
Sales to external customers	1,391	1,389
Operating income (loss)	32	32
Assets	3,903		3,882
Europe
Sales to external customers	1,879	1,373
Operating income (loss)	52	$ (22)
Assets	$ 4,410		$ 4,080