Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 295,096	$ 287,996	$ 286,850	$ 279,836	$ 265,238	$ 259,437	$ 253,998	$ 248,774	$ 1,149,778	$ 1,027,447	$ 917,760
Gross profit	131,939	133,209	127,303	123,232	111,217	108,285	99,795	99,534	515,683	418,831	366,867
Selling, general and administrative expense	71,912	65,493	65,600	59,756	60,993	58,664	59,660	47,399	262,761	226,716	187,864
Operating Income (Loss)	60,027	35,716	61,703	63,476	18,224	49,621	40,135	52,135	220,922	160,115	179,003
Net income	$ 34,802	$ 21,482	$ 36,624	$ 37,333	$ 9,638	$ 27,066	$ 22,638	$ 30,046	$ 130,241	$ 89,388	$ 101,931
Basic net income per share	$ 0.18	$ 0.11	$ 0.19	$ 0.19	$ 0.05	$ 0.14	$ 0.12	$ 0.15	$ 0.66	$ 0.46	$ 0.52
Diluted net income per share	$ 0.17	$ 0.11	$ 0.18	$ 0.19	$ 0.05	$ 0.14	$ 0.11	$ 0.15	$ 0.65	$ 0.45	$ 0.52
Basic weighted average shares	196,516,632	196,445,684	196,270,119	196,217,311	196,173,169	196,062,348	195,747,954	195,745,670	196,363,084	195,933,800	195,735,309
Diluted weighted average shares	199,446,875	199,452,308	198,441,315	198,160,465	198,076,031	198,254,808	197,709,082	197,773,850	199,348,746	198,047,453	197,852,932