Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Net sales	$ 321,783	$ 287,192	$ 607,160	$ 539,778
Cost of sales	249,771	225,759	471,948	430,754
Gross profit	72,012	61,433	135,212	109,024
Selling, general and administrative expenses	40,909	34,992	78,063	67,852
Sale of extrusion assets	1,954	0	1,954	0
Executive succession	0	733	0	1,876
Operating profit	29,149	25,708	55,195	39,296
Interest expense, net	74	85	194	203
Income before income taxes	29,075	25,623	55,001	39,093
Provision for income taxes	10,457	9,758	20,219	14,856
Net income	$ 18,618	$ 15,865	$ 34,782	$ 24,237
Net income per common share:
Basic (in usd per share)	$ 0.78	$ 0.68	$ 1.46	$ 1.05
Diluted (in usd per share)	$ 0.77	$ 0.67	$ 1.43	$ 1.03
Weighted average common shares outstanding:
Basic (in shares)	23,931	23,261	23,842	23,139
Diluted (in shares)	24,303	23,650	24,298	23,553