Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Cost	$ 2,374,407	$ 2,291,188
Accumulated depreciation	(1,520,138)	(1,454,119)
Total	854,269	837,069
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	55,567	55,076
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	546,809	537,474
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 1,772,031	$ 1,698,638