Pension Plans and Other Postretirement Benefits - Pension and Postretirement Plan Contributions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Cost of goods sold	$ 542,518	$ 465,297	$ 1,059,168	$ 932,404
Selling, general and administrative expense	123,637	116,585	225,007	225,513
Other expenses, net	(5,223)	(1,678)	(35,699)	(1,413)
Pension contributions	2,800	2,700	5,900	5,100
Other postretirement benefits payments	$ 700	700	$ 1,200	1,200
Accounting Standards Update 2017-07
Defined Benefit Plan Disclosure [Line Items]
Cost of goods sold		100		300
Selling, general and administrative expense		900		1,800
Other expenses, net		1,000		2,100
Selling, general and administrative expenses | Financial Improvement Plan
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, period contributions		2,000		2,000
Other expenses, net | Financial Improvement Plan
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, period contributions		$ 2,900		$ 2,900