Segment Information - Financial Data by Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Sales to external customers	$ 28,412	$ 27,594	$ 46,063	$ 44,472
Operating income (loss)	3,192	3,078	3,706	3,536
Interest expense, net	74	62	142	117
Other expense (income), net	25	43	28	86
Consolidated income before income taxes	3,093	2,973	3,536	3,333
Assets	74,736		74,736		67,828
United States
Sales to external customers	23,496	22,563	37,721	35,160
Operating income (loss)	2,701	2,587	3,267	2,753
Assets	63,521	56,115	63,521	56,115
Canada
Sales to external customers	3,139	3,310	4,765	4,967
Operating income (loss)	475	521	463	571
Assets	6,221	6,107	6,221	6,107
Europe
Sales to external customers	1,777	1,721	3,577	4,345
Operating income (loss)	16	(30)	(24)	212
Assets	$ 4,994	$ 5,606	$ 4,994	$ 5,606