Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, plant and equipment, gross	$ 684,507	$ 671,662
Less accumulated depreciation	(478,688)	(460,708)
Property, plant and equipment, Net	205,819	210,954
Land [Member]
Property, plant and equipment, gross	6,169	6,169
Buildings And Building Improvements [Member]
Property, plant and equipment, gross	87,605	97,103
Machinery And Equipment [Member]
Property, plant and equipment, gross	538,037	514,450
Furniture And Fixtures [Member]
Property, plant and equipment, gross	10,558	9,343
Vehicles [Member]
Property, plant and equipment, gross	1,268	1,341
Leasehold Improvements [Member]
Property, plant and equipment, gross	35,366	30,122
Construction In Progress Member
Property, plant and equipment, gross	$ 5,504	$ 13,134

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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