Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 157,941	$ 146,450	$ 302,747	$ 278,126
Cost of sales	85,927	85,040	165,563	159,089
Gross profit	72,014	61,410	137,184	119,037
Selling, general and administrative expenses	27,221	24,795	50,490	45,407
Income from operations	44,793	36,615	86,694	73,630
Interest expense, net	251	458	456	1,030
Income before income taxes	44,542	36,157	86,238	72,600
Provision for income taxes	15,760	12,432	29,506	25,170
Net income	$ 28,782	$ 23,725	$ 56,732	$ 47,430
Basic earnings per common share	$ 0.98	$ 0.81	$ 1.93	$ 1.61
Basic weighted average common shares outstanding	29,389,458	29,264,362	29,376,407	29,481,042
Diluted earnings per common share	$ 0.97	$ 0.80	$ 1.92	$ 1.60
Diluted weighted average common shares outstanding	29,550,418	29,477,870	29,555,985	29,694,081
Comprehensive income	$ 28,782	$ 23,725	$ 56,732	$ 47,430