Subsequent Events (Schedule Of Dividends Declared And Distributions Per Unit) (Details) (USD $)	3 Months Ended	6 Months Ended	0 Months Ended	6 Months Ended
Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2013 Series E Cumulative Convertible Preferred Units [Member]	Jun. 30, 2013 Series F Cumulative Convertible Preferred Units [Member]	Apr. 09, 2013 Series G Cumulative Convertible Preferred Units [Member] [Member]	Jun. 30, 2013 Series G Cumulative Convertible Preferred Units [Member] [Member]	Jun. 30, 2013 Subsequent Event [Member] Series E Cumulative Convertible Preferred Units [Member]	Jun. 30, 2013 Subsequent Event [Member] Series F Cumulative Convertible Preferred Units [Member]	Jun. 30, 2013 Subsequent Event [Member] Series G Cumulative Convertible Preferred Units [Member] [Member]	Jun. 30, 2013 Subsequent Event [Member] Common Stock [Member]
Subsequent Event [Line Items]
Dividend and distribution amount						$ 0.334550	$ 0.437500	$ 0.414063	$ 0.367188	$ 0.780000
Dividend and distribution payable date	Jun. 28, 2013	Mar. 29, 2013					Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
Dividend and distribution payable to holders of record on							Sep. 13, 2013	Sep. 13, 2013	Sep. 13, 2013	Sep. 13, 2013
Annual equivalent rate of dividend and distribution			$ 1.750	$ 1.656	$ 1.46875	$ 1.469	$ 1.750	$ 1.656	$ 1.46875	$ 3.120

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

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- Definition

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

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

The amount per share used to calculated dividend payments on preferred stock.

+ References

No definition available.

+ Details

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- Details

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