Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 138,404	$ 136,086	$ 138,082	$ 129,577	$ 132,780	$ 128,808	$ 128,865	$ 119,236	$ 542,149	$ 509,689	$ 449,049
Gross profit	60,307	59,205	60,886	55,383	60,134	57,421	55,624	52,043	235,781	225,222	194,367
Income from operations	8,050	8,547	12,242	8,704	14,217	12,076	7,384	6,489	31,200	31,572	19,839
Income tax expense	145	1,842	3,122	2,289	3,680	2,489	1,366	1,063	7,398	8,598	3,269
Net income	$ 6,409	$ 4,818	$ 7,401	$ 5,174	$ 8,671	$ 7,764	$ 3,716	$ 2,823	$ 23,802	$ 22,974	$ 16,570
Basic (in dollars per share)	$ 0.14	$ 0.11	$ 0.17	$ 0.12	$ 0.20	$ 0.18	$ 0.09	$ 0.07	$ 0.54	$ 0.53	$ 0.39
Diluted (in dollars per share)	$ 0.14	$ 0.11	$ 0.17	$ 0.12	$ 0.20	$ 0.18	$ 0.09	$ 0.07	$ 0.53	$ 0.53	$ 0.39