Property and Equipment (Details) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment	$ 422,200,000	$ 350,900,000
Less accumulated depreciation	(238,400,000)	(205,600,000)
Property and equipment, net	183,793,000	145,302,000
Depreciation expense	27,900,000	28,800,000	31,300,000
Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment	1,700,000	1,700,000
Leasehold improvements under development [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment	2,000,000	5,100,000
Building and improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment	47,500,000	41,300,000
Furniture, equipment and software [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment	$ 371,000,000	$ 302,800,000

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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