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, 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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Property and Equipment, Net (Details) (USD $)	3 Months Ended
Property and Equipment, Net (Details) (USD $)	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 636,779,000		$ 622,998,000
Less: accumulated depreciation	(450,380,000)		(436,381,000)
Property and equipment, net	186,399,000		186,617,000
Depreciation and amortization	18,900,000	16,000,000
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,000,000		4,000,000
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,780,000		10,780,000
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	90,869,000		89,870,000
Capitalized software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	484,053,000		470,469,000
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 47,077,000		$ 47,879,000