Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 233,249	$ 221,659	$ 224,810	$ 203,035	$ 190,897	$ 179,337	$ 186,549	$ 171,069	$ 882,753	$ 727,852	$ 603,838
Gross profit	104,666	102,039	100,009	88,056	85,656	80,514	84,141	75,942	394,770	326,253	265,025
Income from operations	13,661	21,061	15,114	8,781	13,219	879	13,362	5,609	58,617	33,069	34,876
Income tax expense	3,022	2,766	624	1,090	4,474	1,364	1,830	690	7,502	8,358	5,265
Net income	$ 9,188	$ 16,619	$ 10,941	$ 5,269	$ 6,806	$ (3,569)	$ 9,483	$ 14,803	$ 42,017	$ 27,523	$ 20,121
Basic (in dollars per share)	$ 0.17	$ 0.31	$ 0.22	$ 0.10	$ 0.14	$ (0.07)	$ 0.19	$ 0.33	$ 0.80	$ 0.56	$ 0.45
Diluted (in dollars per share)	$ 0.16	$ 0.30	$ 0.21	$ 0.10	$ 0.13	$ (0.07)	$ 0.19	$ 0.32	$ 0.78	$ 0.55	$ 0.45