Consolidated Statements of Income $ in Thousands		12 Months Ended
		Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares
Income Statement [Abstract]
Net Sales		$ 4,448,875	$ 4,089,854	$ 3,612,914
Cost of Goods Sold	[1]	3,759,112	3,455,306	3,101,065
Gross profit		689,763	634,548	511,849
Selling, general and administrative expenses	[1]	308,376	305,173	219,926
Rationalization charges		6,253	5,826	19,061
Other pension and postretirement income	[1]	(36,966)	(33,441)	(26,868)
Income Before Interest and Income Taxes		412,100	356,990	299,730
Interest and other debt expense before loss on early extinguishment of debt		116,306	110,257	67,813
Loss on early extinguishment of debt		2,493	7,052	0
Interest and other debt expense		118,799	117,309	67,813
Income before income taxes		293,301	239,681	231,917
Provision (benefit) for income taxes		69,307	(29,978)	78,566
Net income		$ 223,994	$ 269,659	$ 153,351
Basic net income per share (in dollars per share) | $ / shares	[2]	$ 2.03	$ 2.44	$ 1.28
Diluted net income per share (in dollars per share) | $ / shares	[2]	$ 2.01	$ 2.42	$ 1.27
Stock split ratio (in shares)				2

[1] Cost of goods sold, selling, general and administrative expenses and other pension and postretirement income include the impact of the Accounting Standards Update issued by the Financial Accounting Standards Board which amended the presentation of net periodic pension and postretirement benefit costs to report certain components, including interest cost, expected return on the plan assets, amortization of prior service cost or credits and actuarial gains and losses, separately. For 2017 and 2016, these items have been reclassified from cost of goods sold and selling, general and administrative expenses to other pension and postretirement income.

[2] Per share amounts for 2016 have been retroactively adjusted for the two-for-one stock split discussed in Note 1.