Quarterly Financial Information (Unaudited) (Summary of Quarterly Financial Results) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales	$ 99,894	$ 99,029	$ 90,468	$ 96,754	$ 101,051	$ 97,535	$ 97,995	$ 94,167	$ 397,969	$ 378,924	$ 383,588
Gross profit	20,329	21,365	17,304	19,241	23,037	21,993	20,494	19,269	85,225	77,807	67,506
Net income	$ 4,133	$ 4,492	$ 2,427	$ 3,912	$ 5,955	$ 6,592	$ 4,575	$ 3,875	$ 19,155	$ 16,806	$ 13,779
Basic earnings per share:
Continuing operations	$ 0.25	$ 0.27	$ 0.15	$ 0.23	$ 0.36	$ 0.39	$ 0.28	$ 0.23	$ 1.16	$ 1.01	$ 0.54
Net income	$ 0.25	$ 0.27	$ 0.15	$ 0.23	$ 0.36	$ 0.39	$ 0.28	$ 0.23	$ 1.16	$ 1.01	$ 0.82
Diluted earnings per share:
Continuing operations	$ 0.25	$ 0.26	$ 0.14	$ 0.23	$ 0.35	$ 0.39	$ 0.27	$ 0.23	$ 1.14	$ 0.99	$ 0.54
Net income	$ 0.25	$ 0.26	$ 0.14	$ 0.23	$ 0.35	$ 0.39	$ 0.27	$ 0.23	$ 1.14	$ 0.99	$ 0.82