Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 1,306,999	$ 1,266,930	$ 3,378,383	$ 3,094,150
Cost of goods sold	1,102,892	1,061,289	2,840,991	2,611,836
Gross profit	204,107	205,641	537,392	482,314
Selling, general and administrative expenses	73,690	75,149	228,691	232,461
Rationalization charges	288	561	1,483	4,485
Other pension and postretirement income	(8,326)	(8,635)	(27,536)	(25,192)
Income before interest and income taxes	138,455	138,566	334,754	270,560
Interest and other debt expense before loss on early extinguishment of debt	28,199	30,583	88,602	80,207
Loss on early extinguishment of debt	0	0	2,493	7,052
Interest and other debt expense	28,199	30,583	91,095	87,259
Income before income taxes	110,256	107,983	243,659	183,301
Provision for income taxes	25,517	35,601	57,857	59,762
Net income	$ 84,739	$ 72,382	$ 185,802	$ 123,539
Earnings per share
Basic net income per share (usd per share)	$ 0.77	$ 0.66	$ 1.68	$ 1.12
Diluted net income per share (usd per share)	0.76	0.65	1.66	1.11
Common Stock, Dividends, Per Share, Declared	$ 0.10	$ 0.09	$ 0.30	$ 0.27
Weighted average number of shares
Basic (in shares)	110,657	110,391	110,599	110,327
Effect of dilutive securities (in shares)	1,036	1,036	1,010	996
Diluted (in shares)	111,693	111,427	111,609	111,323