Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Cost	$ 2,547,966			$ 2,468,930
Accumulated depreciation	(1,569,345)			(1,523,260)
Total	978,621			945,670
Depreciation expense	46,325	$ 44,501	$ 89,530
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	70,914			68,575
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	615,387			597,523
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 1,861,665			$ 1,802,832