Subsequent Events - Additional Information (Detail) (Dividend Declared, USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended
May 31, 2013
Dividend Declared
Subsequent Event [Line Items]
Special non-recurring dividend, declared date	May 06, 2013
Special non-recurring dividend, declared per share	$ 1.50
Special non-recurring dividend, expected approximate total amount	$ 130
Special non-recurring dividend, payable date	Jul. 02, 2013
Special non-recurring dividend, record date	Jun. 12, 2013

Expected Approximate Total Amount of Special Non-Recurring Dividend

No definition available.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

+ Details

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Period Type:	duration

- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

+ Details

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- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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- Details

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