Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Consolidated Statements Of Income (Loss) [Abstract]
Net sales	$ 602,820	$ 608,136
Cost of sales	549,020	549,818
Gross profit	53,800	58,318
Selling, general and administrative expenses	33,770	35,750
Amortization of intangible assets	2,367	2,366
Restructuring charges and other costs	1,576	2,235
Income from operations	16,087	17,967
Interest expense	(1,609)	(2,428)
Interest income	1,297	1,933
Other income	1,604	43
Income before income taxes	17,379	17,515
Income tax expense	3,606	41,156
Net income (loss)	$ 13,773	$ (23,641)
Earnings (loss) per share:
Basic	$ 0.34	$ (0.49)
Diluted	$ 0.34	$ (0.49)
Weighted-average number of shares outstanding:
Basic	40,630	48,517
Diluted	40,853	48,517