Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment
Gross property, plant and equipment	$ 1,854,195	$ 1,916,469
Less: Accumulated depreciation	(1,335,944)	(1,352,434)
Property, plant and equipment, net	518,251	564,035
Land
Property, Plant and Equipment
Gross property, plant and equipment	10,906	10,932
Land improvements
Property, Plant and Equipment
Gross property, plant and equipment	15,172	15,277
Buildings and improvements
Property, Plant and Equipment
Gross property, plant and equipment	189,864	191,356
Machinery and equipment
Property, Plant and Equipment
Gross property, plant and equipment	1,614,597	1,661,914
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 23,656	$ 36,990