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Aggregate dividends paid 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

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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

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Stockholders' Equity (Dividends) (Details) (USD $)	3 Months Ended												12 Months Ended			0 Months Ended
Stockholders' Equity (Dividends) (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	May 03, 2013 Dividend Declared [Member]
Dividends [Line Items]
Cash dividends paid	$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 0.32	$ 0.32	$ 0.32	$ 0.29	$ 0.29	$ 0.25	$ 0.25	$ 0.22	$ 1.60	$ 1.25	$ 1.01
Dividends payable, declaration date																May 02, 2013
Cash dividend declared																$ 0.48
Dividends payable date																Jun. 28, 2013
Dividends payable, date of record																Jun. 14, 2013