Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	$ 369,921	$ 338,315
Accumulated Depreciation and Amortization	259,524	229,540
Property, Plant and Equipment, Net	110,397	108,775
Depreciation expense	37,888	36,780	36,728
Land [Member]
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	4,308	4,228
Buildings [Member]
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	74,609	69,871
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	$ 291,004	$ 264,216

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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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Gross amount of long-lived 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, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived 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, furniture and fixtures, and computer equipment.

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