Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 611,428	$ 596,189
Less accumulated depreciation	353,274	331,471
Net property, plant and equipment	258,154	264,718
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	20,168	19,845
Building
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	86,498	89,873
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	449,805	437,320
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	13,662	13,663
Software
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	19,987	20,893
Construction in Progress
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 21,308	$ 14,595