Property 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]
Accumulated depreciation	$ (192,165)	$ (184,316)
Total	182,839	188,018
Depreciation expense	20,945	18,551	18,022
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	13,000	13,052
Building and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	130,105	134,513
Manufacturing and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	217,047	209,939
Aviation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,852	$ 14,830

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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