Estimated Useful Lives and Accumulated Depreciation for Furniture, Equipment and Software (Detail)	12 Months Ended
Dec. 31, 2012
Furniture and Fixtures \| Minimum
Property Plant and Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life	3 years
Furniture and Fixtures \| Maximum
Property Plant and Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life	7 years
Software \| Minimum
Property Plant and Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life	3 years
Software \| Maximum
Property Plant and Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life	5 years

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration