Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Cost	$ 2,340,899		$ 2,340,899		$ 2,232,129
Accumulated depreciation	(1,461,279)		(1,461,279)		(1,389,811)
Total	879,620		879,620		842,318
Depreciation expense	34,096	$ 32,145	102,016	$ 97,364
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	59,511		59,511		56,583
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	549,617		549,617		527,192
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 1,731,771		$ 1,731,771		$ 1,648,354