Summary of the Purchase Price Allocation (Parenthetical) (Detail)	1 Months Ended	12 Months Ended
Nov. 01, 2009 Year	Dec. 31, 2011 Year
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Acquired intangible assets, estimated useful life, minimum (in years)	1	1
Acquired intangible assets, estimated useful life, maximum (in years)	10	10

The maximum useful life of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 35

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15217-109273

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 35

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15300-109273

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15211-109273

Name:	us-gaap_FiniteLivedIntangibleAssetsUsefulLifeMaximum
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration