Investments in Unconsolidated Real Estate Joint Ventures Unconsolidated Real Estate Joint Ventures (Details) (USD $) In Thousands, unless otherwise specified				3 Months Ended
Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Partnership Interest [Member]	Mar. 31, 2012 Houston [Member] SquareFeet	Mar. 31, 2012 Deer Park Warehouse [Member] SquareFeet	Mar. 31, 2012 Deer Park [Member] SquareFeet	Mar. 31, 2012 Wisconsin Dells [Member] SquareFeet	Mar. 31, 2012 National Harbor [Member] SquareFeet	Mar. 31, 2012 RioCan Canda [Member] SquareFeet	Mar. 31, 2012 Equity Method Investee [Member] SquareFeet
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage				50.00%	33.30%	33.30%	50.00%	50.00%	50.00%	50.00%
Square Footage of Real Estate Property				0	29,253	741,976	265,086	0	157,382	0
Equity Method Investments	$ 48,500	$ 28,500	$ 48,500	$ 13,900	$ 0	$ 4,700	$ 4,000	$ 900	$ 24,800	$ 200
Joint Venture Debt	$ 273,500			$ 0	$ 2,300	$ 246,900	$ 24,300	$ 0	$ 0	$ 0

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

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