Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Cost	$ 2,636,318		$ 2,636,318		$ 2,468,930
Accumulated depreciation	(1,623,553)		(1,623,553)		(1,523,260)
Total	1,012,765		1,012,765		945,670
Depreciation expense	49,986	$ 42,786	141,029	$ 132,316
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	72,514		72,514		68,575
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	633,137		633,137		597,523
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 1,930,667		$ 1,930,667		$ 1,802,832