Property, Equipment and Leasehold Improvements, Less Accumulated Depreciation and Amortization (Detail) (USD $) In Thousands, unless otherwise specified			12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Computer equipment and software Year	Dec. 31, 2011 Furniture and equipment Year	Dec. 31, 2011 Leasehold improvements Year
Property, Plant and Equipment [Line Items]
Useful Life, minimum (in years)			2	3	2
Useful Life, maximum (in years)			7	8	15
Computer equipment and software	$ 130,733	$ 123,988
Furniture and equipment	34,828	32,093
Leasehold improvements	63,773	46,516
Property, Plant and Equipment, Gross, Total	229,334	202,597
Less - accumulated depreciation and amortization	(161,202)	(154,983)
Property, equipment and leasehold improvements, net	$ 68,132	$ 47,614

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, 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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