Property And Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 403,624	$ 395,005
Less allowance for depreciation	(326,578)	(316,500)
Property and equipment, net	77,046	78,505
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	305,471	299,205
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	75,715	73,830
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,192	11,947
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 10,246	$ 10,023