Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 648,248	$ 640,049
Less accumulated depreciation	391,856	367,515
Net property, plant and equipment	256,392	272,534
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	19,524	19,871
Buildings
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	102,666	102,236
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	473,004	470,862
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	14,208	14,313
Software
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	22,733	23,630
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 16,113	$ 9,137