Quarterly Results of Operations (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Results of Operations (Unaudited)
Net sales	$ 85,447	$ 75,534	$ 69,169	$ 66,907	$ 74,218	$ 63,741	$ 60,661	$ 51,549	$ 297,057	$ 250,169	$ 206,730
Gross Profit	7,037	5,698	5,590	5,567	7,058	5,757	5,601	4,825	23,892	23,241	20,010
Net income	$ 1,804	$ 1,352	$ 1,304	$ 1,029	$ 1,974	$ 1,494	$ 1,228	$ 843	$ 5,489	$ 5,539	$ 4,421
Basic net income per common share (in dollars per share)	$ 0.40	$ 0.30	$ 0.29	$ 0.23	$ 0.45	$ 0.34	$ 0.28	$ 0.19	$ 1.23	$ 1.26	$ 1.01
Diluted net income per common share (in dollars per share)	$ 0.39	$ 0.29	$ 0.28	$ 0.22	$ 0.43	$ 0.33	$ 0.26	$ 0.18	$ 1.19	$ 1.20	$ 0.98