Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net sales	$ 362,085	$ 321,783	$ 723,542	$ 607,160
Cost of sales	280,025	249,771	565,079	471,948
Gross profit	82,060	72,012	158,463	135,212
Selling, general and administrative expenses	48,426	40,909	92,991	78,063
Sale of extrusion assets	0	(1,954)	0	(1,954)
Operating profit	33,634	29,149	65,472	55,195
Interest expense, net	615	74	804	194
Income before income taxes	33,019	29,075	64,668	55,001
Provision for income taxes	12,150	10,457	23,726	20,219
Net income	$ 20,869	$ 18,618	$ 40,942	$ 34,782
Net income per common share:
Basic (in usd per share)	$ 0.86	$ 0.78	$ 1.69	$ 1.46
Diluted (in usd per share)	$ 0.85	$ 0.77	$ 1.67	$ 1.43
Weighted average common shares outstanding:
Basic (in shares)	24,279	23,931	24,247	23,842
Diluted (in shares)	24,615	24,303	24,578	24,298