Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 565,153	$ 479,616	$ 440,804
Cost of sales	321,780	292,521	285,935
Gross profit	243,373	187,095	154,869
Selling, general and administrative expenses	100,993	83,140	77,463
Income from operations	142,380	103,955	77,406
Interest expense, net	461	1,125	619
Income before income taxes	141,919	102,830	76,787
Provision for income taxes	46,791	34,983	28,689
Net income	$ 95,128	$ 67,847	$ 48,098
Basic earnings per common share	$ 3.24	$ 2.31	$ 1.53
Basic weighted average common shares outstanding	29,392,559	29,394,559	31,350,542
Diluted earnings per common share	$ 3.22	$ 2.29	$ 1.52
Diluted weighted average common shares outstanding	29,575,460	29,612,669	31,682,509
Comprehensive income	$ 95,128	$ 67,847	$ 48,098