Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements Of Income [Abstract]
Sales	$ 570,083	$ 613,864	$ 1,693,944	$ 1,775,218
Cost of sales	535,448	566,672	1,583,934	1,636,535
Gross profit	34,635	47,192	110,010	138,683
Selling, general and administrative expenses	22,874	23,379	67,822	68,927
Restructuring charges	145	452	625	2,149
Income from operations	11,616	23,361	41,563	67,607
Interest expense	(334)	(343)	(997)	(1,022)
Interest income	446	394	1,293	1,208
Other income (expense)	(202)	1,212	94	162
Income before income taxes	11,526	24,624	41,953	67,955
Income tax expense (benefit)	(8,341)	2,155	(7,128)	7,207
Net income	$ 19,867	$ 22,469	$ 49,081	$ 60,748
Earnings per share:
Basic	$ 0.34	$ 0.36	$ 0.82	$ 0.97
Diluted	$ 0.34	$ 0.36	$ 0.81	$ 0.96
Weighted-average number of shares outstanding:
Basic	58,615	61,712	59,889	62,597
Diluted	58,879	62,103	60,391	63,162