Property Acquisitions, Discontinued Operations, And Assets Held For Sale Property Acquisitions, Discontinued Operations, And Assets Held For Sale (Selected data regarding acquisition) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Property Acquisitions, Discontinued Operations, And Assets Held For Sale [Abstract]
Cash consideration	$ 99.5
Fair value of our 20% ownership interest held before the acquisition	24.9
Debt assumed	272.6
Net other assets/liabilities acquired	1.1
Acquisition date fair value	$ 398.1

Property Acquisitions, Discontinued Operations, And Assets Held For Sale Property Acquisitions, Discontinued Operations, And Assets Held For Sale (Selected data regarding acquisition) (Details) (USD $)
In Millions, unless otherwise specified

Mar. 31, 2012

Property Acquisitions, Discontinued Operations, And Assets Held For Sale [Abstract]

$ 99.5

Fair value of our 20% ownership interest held before the acquisition

24.9

Debt assumed

272.6

Net other assets/liabilities acquired

1.1

Acquisition date fair value

$ 398.1

- Definition

Fair Value of the liabilities incurred by the acquirer to former owners of the acquiree, including the fair value of any contingent consideration. If liabilities transferred as consideration remain within the combined entity after the business combination (for example, because the assets or liabilities were transferred to the acquiree rather than to its former owners), and the acquirer therefore retains control of them; in that situation, the acquirer measures those liabilities at their carrying amounts immediately before the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 39, 40, 41

-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.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(3)

-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