Quarterly Results of Operations (Unaudited) - Summary of Unaudited Quarterly Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 153,761	$ 125,632	$ 106,680	$ 102,528	$ 90,081	$ 93,023	$ 96,305	$ 93,797	$ 488,601	$ 373,206	$ 370,084
Income from operations	8,560	2,552	8,237	8,338	6,474	7,794	7,920	5,639	27,687	27,827	25,071
Net income	$ 1,619	$ (3,840)	$ 5,200	$ 5,238	$ 4,485	$ 5,052	$ 4,770	$ 2,871	$ 8,217	$ 17,178	$ 24,268
Basic net income per share	$ 0.09	$ (0.21)	$ 0.29	$ 0.30	$ 0.25	$ 0.29	$ 0.28	$ 0.17	$ 0.46	$ 1.00	$ 1.43
Diluted net income per share	$ 0.08	$ (0.21)	$ 0.29	$ 0.29	$ 0.25	$ 0.29	$ 0.28	$ 0.17	$ 0.45	$ 1.00	$ 1.42
Weighted average shares outstanding:
Basic number of shares	18,970	17,979	17,779	17,656	17,527	17,302	17,136	17,055	17,887	17,176	17,009
Effect of dilutive stock options	347		393	306	290	148	36	107	366	84	105
Diluted number of shares	19,317	17,979	18,172	17,962	17,817	17,450	17,172	17,162	18,253	17,260	17,114