Segment Information - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Sales to external customers	$ 43,525	$ 35,775
Operating income	2,968	2,010
Interest expense, net	221	315
Other expense, net	77	43
Consolidated income before income taxes	2,670	1,652
Assets	135,314		$ 129,868
United States Segment
Sales to external customers	36,048	30,443
Operating income	2,133	1,571
Assets	118,158		113,831
Canada Segment
Sales to external customers	3,333	2,422
Operating income	370	205
Assets	8,340		7,432
Europe Segment
Sales to external customers	4,144	2,910
Operating income	465	$ 234
Assets	$ 8,816		$ 8,605