Segment Information - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Sales to external customers	$ 44,042	$ 40,220	$ 79,817	$ 71,590
Operating income	4,383	3,768	6,392	5,303
Interest expense, net	234	491	554	994
Other (income) expense, net	(1)	14	37	12
Consolidated income before income taxes	4,150	3,263	5,801	4,297
Assets	123,536		123,536		$ 110,749
United States Segment
Sales to external customers	38,476	34,958	68,922	62,423
Operating income	3,685	3,271	5,253	4,529
Assets	109,807		109,807		98,578
Canada Segment
Sales to external customers	2,381	2,216	4,800	3,628
Operating income	366	360	573	495
Assets	6,538		6,538		6,168
Europe Segment
Sales to external customers	3,185	3,046	6,095	5,539
Operating income	332	$ 137	566	$ 279
Assets	$ 7,191		$ 7,191		$ 6,003