Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, plant and equipment, gross	$ 618,516	$ 572,523
Less accumulated depreciation	(432,043)	(406,375)
Property, plant and equipment, Net	186,473	166,148
Land [Member]
Property, plant and equipment, gross	6,169	6,169
Buildings And Building Improvements [Member]
Property, plant and equipment, gross	90,577	90,330
Machinery And Equipment [Member]
Property, plant and equipment, gross	476,466	445,537
Furniture And Fixtures [Member]
Property, plant and equipment, gross	8,468	8,089
Vehicles [Member]
Property, plant and equipment, gross	1,244	1,231
Leasehold Improvements [Member]
Property, plant and equipment, gross	25,153	21,167
Construction In Progress Member
Property, plant and equipment, gross	$ 10,439	$ 0

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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-Name Accounting Standards Codification
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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