Geographic and Business Segment Information - Additional Information (Detail) (Foreign)	Dec. 31, 2011 Country
Foreign
Segment Reporting Information [Line Items]
Number of countries in which entity operates	6

The number of countries in which the entity operates as of balance sheet date.

No definition available.

Name:	us-gaap_NumberOfCountriesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant