Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Net sales	$ 294,271	$ 250,851	$ 901,431	$ 790,629
Cost of sales	231,788	194,725	703,736	625,479
Gross profit	62,483	56,126	197,695	165,150
Selling, general and administrative expenses	39,412	33,296	117,475	101,148
Sale of extrusion assets	0	0	1,954	0
Executive succession	0	0	0	1,876
Operating profit	23,071	22,830	78,266	62,126
Interest expense, net	130	76	324	279
Income before income taxes	22,941	22,754	77,942	61,847
Provision for income taxes	7,453	7,949	27,672	22,805
Net income	$ 15,488	$ 14,805	$ 50,270	$ 39,042
Net income per common share:
Basic (in usd per share)	$ 0.65	$ 0.63	$ 2.11	$ 1.68
Diluted (in usd per share)	$ 0.64	$ 0.62	$ 2.07	$ 1.65
Weighted average common shares outstanding:
Basic (in shares)	23,935	23,451	23,870	23,243
Diluted (in shares)	24,301	23,838	24,300	23,644