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

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

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- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

+ References

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- Definition

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

+ References

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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.

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- Definition

Amount of a stock repurchase plan authorized by an entity's Board of Directors.

+ References

No definition available.

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Subsequent Events - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	6 Months Ended	1 Months Ended
	Jun. 30, 2013	Jun. 28, 2013 Class A Common Stock [Member]	May 01, 2013 Class A Common Stock [Member]	Jul. 30, 2013 Subsequent Event [Member]	Jul. 30, 2013 Subsequent Event [Member] Class A Common Stock [Member]	Jul. 30, 2013 Subsequent Event [Member] Class B Common Stock [Member]
Subsequent Event [Line Items]
Declared a quarterly cash dividend					$ 0.12	$ 0.12
Dividend declared date					Jul. 30, 2013	Jul. 30, 2013
Dividends payable, date to be paid					Sep. 06, 2013	Sep. 06, 2013
Date of record					Aug. 23, 2013	Aug. 23, 2013
Company's repurchase and redemption authority amount		$ 250	$ 100	$ 250