Estimated Useful Lives of the Assets (Detail)	12 Months Ended
	Dec. 31, 2011
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Minimum useful life (in years)	5
Maximum useful life (in years)	7
Equipment and software
Property, Plant and Equipment [Line Items]
Minimum useful life (in years)	2
Maximum useful life (in years)	5
Improvements
Property, Plant and Equipment [Line Items]
Minimum useful life (in years)	5
Maximum useful life (in years)	15
Buildings
Property, Plant and Equipment [Line Items]
Minimum useful life (in years)	10
Maximum useful life (in years)	51