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

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=27012166&loc=d3e187085-122770

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- Definition

Date the declared dividend will be paid, 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

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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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Subsequent Events Subsequent Events (Details) (USD $)	12 Months Ended
Subsequent Events Subsequent Events (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Subsequent Event [Line Items]
Dividends declared per share (usd per share)	$ 1.25	$ 1.00	$ 0.79
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared	Feb. 11, 2015
Dividends Payable, Date to be Paid	Mar. 05, 2015
Dividends Payable, Date of Record	Feb. 23, 2015
Dividend Declared [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends declared per share (usd per share)	$ 0.5