Unrecognized Share-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2011 Year
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 35,473
Stock option
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	14,436
Average Expected Recognition Period - in Years	2.85
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 21,037
Average Expected Recognition Period - in Years	2.80

The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration