Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Capital leases included in plant, property and equipment	$ 5,500	$ 8,700
Gross property, plant and equipment	1,848,518	1,757,486
Less: Accumulated depreciation	(1,368,771)	(1,267,231)
Property, plant and equipment, net	479,747	490,255	$ 564,035
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	10,840	10,606
Land improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 14,996	15,032
Land improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Land improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	20 years
Buildings and improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 198,582	185,657
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	40 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 1,599,713	1,525,156
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	20 years
Uncompleted construction
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 24,387	$ 21,035