Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment
Gross property, plant and equipment	$ 1,704,360	$ 1,806,603
Less: Accumulated depreciation	(1,171,011)	(1,244,817)
Property, plant and equipment, net	533,349	561,786
Land
Property, Plant and Equipment
Gross property, plant and equipment	29,811	30,409
Land improvements
Property, Plant and Equipment
Gross property, plant and equipment	17,822	19,155
Buildings and improvements
Property, Plant and Equipment
Gross property, plant and equipment	180,907	182,795
Machinery and equipment
Property, Plant and Equipment
Gross property, plant and equipment	1,418,493	1,518,652
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 57,327	$ 55,592