Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 665,706	$ 684,507
Less accumulated depreciation	(480,434)	(478,688)
Property, plant and equipment, Net	185,272	205,819
Land [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	5,689	6,169
Buildings And Building Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	85,672	87,605
Machinery And Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	521,382	538,037
Furniture And Fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	10,426	10,558
Vehicles [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,142	1,268
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	39,716	35,366
Construction In Progress Member
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,679	$ 5,504

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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