Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment
Gross property, plant and equipment	$ 1,845,483	$ 1,806,603
Less: Accumulated depreciation	(1,211,131)	(1,244,817)
Property, plant and equipment, net	634,352	561,786
Land
Property, Plant and Equipment
Gross property, plant and equipment	75,579	30,409
Land improvements
Property, Plant and Equipment
Gross property, plant and equipment	18,461	19,155
Buildings and improvements
Property, Plant and Equipment
Gross property, plant and equipment	219,883	182,795
Machinery and equipment
Property, Plant and Equipment
Gross property, plant and equipment	1,473,061	1,518,652
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 58,499	$ 55,592