Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment, gross	$ 671,662	$ 618,516
Less accumulated depreciation	(460,708)	(432,043)
Property, plant and equipment, Net	210,954	186,473
Land [Member]
Property, plant and equipment, gross	6,169	6,169
Buildings And Building Improvements [Member]
Property, plant and equipment, gross	97,103	90,577
Machinery And Equipment [Member]
Property, plant and equipment, gross	514,450	476,466
Furniture And Fixtures [Member]
Property, plant and equipment, gross	9,343	8,468
Vehicles [Member]
Property, plant and equipment, gross	1,341	1,244
Leasehold Improvements [Member]
Property, plant and equipment, gross	30,122	25,153
Construction In Progress Member
Property, plant and equipment, gross	$ 13,134	$ 10,439

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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