Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 1,012,280	$ 805,407
Cost of goods sold	852,246	687,427
Gross profit	160,034	117,980
Selling, general and administrative expenses	76,747	68,659
Rationalization charges	703	885
Other pension and postretirement income	(9,598)	(8,326)
Income before interest and income taxes	92,182	56,762
Interest and other debt expense before loss on early extinguishment of debt	30,481	20,418
Loss on early extinguishment of debt	0	2,677
Interest and other debt expense	30,481	23,095
Income before income taxes	61,701	33,667
Provision for income taxes	15,980	10,435
Net income	$ 45,721	$ 23,232
Earnings per share
Basic net income per share (usd per share)	$ 0.41	$ 0.21	[1]
Diluted net income per share (usd per share)	0.41	0.21	[1]
Dividends per share (usd per share)	$ 0.10	$ 0.09	[1]
Weighted average number of shares
Basic (in shares)	110,492	110,231	[1]
Effect of dilutive securities (in shares)	1,066	984	[1]
Diluted (in shares)	111,558	111,215	[1]

[1] Per share and share amounts for 2017 have been retroactively adjusted for the two-for-one stock split discussed in Note 1.