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, Gross	$ 552,800	$ 531,819
Less accumulated depreciation	(362,620)	(346,500)
Property, plant and equipment, Net	190,180	185,319
Land [Member]
Property, plant and equipment, Gross	6,339	6,359
Buildings And Building Improvements [Member]
Property, plant and equipment, Gross	92,599	92,267
Machinery And Equipment [Member]
Property, plant and equipment, Gross	426,780	410,183
Furniture And Fixtures [Member]
Property, plant and equipment, Gross	7,843	7,934
Vehicles [Member]
Property, plant and equipment, Gross	1,002	174
Leasehold Improvements [Member]
Property, plant and equipment, Gross	18,237	14,767
Construction in Progress [Member]
Property, plant and equipment, Gross	$ 0	$ 135