Property, Plant and Equipment, Net (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Property, Plant and Equipment
Property, plant and equipment, gross	$ 421,008	$ 394,705	$ 388,479
Accumulated depreciation and amortization	(215,562)	(201,540)	(199,614)
Property, plant and equipment excluding capital projects in progress, net	205,446	193,165	188,865
Capital projects in progress	5,686	2,551	2,151
Property, plant and equipment, net	211,132	195,716	191,016
Land
Property, Plant and Equipment
Property, plant and equipment, gross	32,282	28,996	28,889
Buildings and site improvements
Property, Plant and Equipment
Property, plant and equipment, gross	170,761	153,597	152,167
Leasehold improvements
Property, Plant and Equipment
Property, plant and equipment, gross	5,047	3,820	3,736
Machinery and equipment
Property, Plant and Equipment
Property, plant and equipment, gross	$ 212,918	$ 208,292	$ 203,687

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 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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