Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Cost	$ 2,486,059		$ 2,468,930
Accumulated depreciation	(1,539,683)		(1,523,260)
Total	946,376		945,670
Depreciation expense	44,718	$ 45,029
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	69,187		68,575
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	601,612		597,523
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 1,815,260		$ 1,802,832