Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 635,594	$ 622,452
Less accumulated depreciation	357,616	356,790
Net property, plant and equipment	277,978	265,662
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	20,353	21,452
Buildings
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	97,485	89,734
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	448,241	459,244
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	15,431	14,468
Software
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	19,950	20,490
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 34,134	$ 17,064