Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Consolidated Statements Of Income [Abstract]
Sales	$ 566,501	$ 549,225
Cost of sales	517,441	498,908
Gross profit	49,060	50,317
Selling, general and administrative expenses	32,651	28,456
Amortization of intangible assets	2,481	2,804
Restructuring charges and other costs	1,511	2,789
Income from operations	12,417	16,268
Interest expense	(2,225)	(2,334)
Interest income	1,074	264
Other expense, net	(81)	(223)
Income before income taxes	11,185	13,975
Income tax expense	1,498	2,923
Net income	$ 9,687	$ 11,052
Earnings per share:
Basic	$ 0.2	$ 0.22
Diluted	$ 0.19	$ 0.22
Weighted-average number of shares outstanding:
Basic	49,511	49,848
Diluted	50,080	50,287