The additional amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ 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 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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Balance Type:	na
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- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount remaining of a stock repurchase plan authorized.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:

Common Stock and Treasury Stock - Additional Information (Detail) (USD $)	3 Months Ended	36 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Feb. 28, 2014	Jul. 31, 2013	Feb. 29, 2012	Dec. 31, 2011	Sep. 13, 2012
Maximum stock authorized to purchase under stock repurchase program					$ 262,100,000	$ 210,000,000
Increase in maximum stock authorized to purchase under stock repurchase program			100,000,000	100,000,000	52,100,000
Repurchase of common stock, shares	0	37,108,467
Repurchase of common stock, value		395,800,000
Maximum [Member]
Maximum stock authorized to purchase under stock repurchase program							113,000,000
Stock authorized to purchase under stock repurchase program, shares							7,500,000
Remaining value of shares authorized for purchase under the stock repurchase program	138,300,000