Supplemental balance sheet and cash flow information (property, plant and equipment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Property, plant and equipment [Abstract]
Property, plant and equipment - gross	$ 466,253	$ 458,640
Accumulated depreciation	(352,842)	(338,419)
Property, plant and equipment - net	113,411	120,221
Trade name [Member]
Indefinite-lived [Abstract]
Gross carrying amount	19,100	19,100
Net carrying amount	19,100	19,100
Land and Improvements [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment - gross	33,970	33,981
Accumulated depreciation	(8,848)	(8,517)
Property, plant and equipment - net	25,122	25,464
Building and Improvements [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment - gross	122,262	120,672
Accumulated depreciation	(69,619)	(65,359)
Property, plant and equipment - net	52,643	55,313
Machinery and Equipment [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment - gross	310,021	303,987
Accumulated depreciation	(274,375)	(264,543)
Property, plant and equipment - net	$ 35,646	$ 39,444

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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