Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 206,692	$ 157,941	$ 377,899	$ 302,747
Cost of sales	115,577	85,927	210,071	165,563
Gross profit	91,115	72,014	167,828	137,184
Selling, general and administrative expenses	33,513	27,221	62,472	50,490
Income from operations	57,602	44,793	105,356	86,694
Interest expense, net	369	251	598	456
Income before income taxes	57,233	44,542	104,758	86,238
Provision for income taxes	14,413	15,760	24,828	29,506
Net income	$ 42,820	$ 28,782	$ 79,930	$ 56,732
Basic earnings per common share	$ 0.73	$ 0.49	$ 1.36	$ 0.97
Basic weighted average common shares outstanding	58,760,753	58,778,916	58,807,694	58,752,814
Diluted earnings per common share	$ 0.73	$ 0.49	$ 1.35	$ 0.96
Diluted weighted average common shares outstanding	59,051,413	59,100,836	59,125,258	59,111,970
Comprehensive income	$ 42,820	$ 28,782	$ 79,930	$ 56,732