Impairment (Summary Of Impairment Charges)(Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Asset Impairment [Line Items]
Total reported in continuing operations	$ 4,293		$ 18,891		$ 11,145		$ 19,661
Total impairment charges	5,051		21,325		15,074		22,550
Equity in losses of real estate joint ventures and partnerships, net	(15,695)		3,579		(11,620)		6,976
Net impact of impairment charges	24,940		21,325		34,963		22,660
Tax Increment Revenue Bonds [Member]
Asset Impairment [Line Items]
Impairment losses related to tax increment revenue bonds	0	[1]	18,737	[1]	0	[1]	18,737	[1]
Property Marketed For Sale Or Sold [Member]
Asset Impairment [Line Items]
Impairment losses related to property	4,293	[2]	154	[2]	4,537	[2]	924	[2]
Investments In Real Estate Joint Ventures And Partnerships [Member]
Asset Impairment [Line Items]
Impairment losses related to partially owned real estate joint ventures and partnerships	0	[3]	0	[3]	6,608	[3]	0	[3]
Property Held For Sale Or Sold [Member]
Asset Impairment [Line Items]
Impairment losses related to property	758	[4]	2,434	[4]	3,929	[4]	2,889	[4]
Impairment Charges At Equity In Losses Of Real Estate Joint Ventures And Partnerships, Net [Member]
Asset Impairment [Line Items]
Equity in losses of real estate joint ventures and partnerships, net	$ 19,889		$ 0		$ 19,889		$ 110

[1] During 2011, the tax increment revenue bonds were remarketed by the Agency. All of the outstanding bonds were recalled, and new bonds were issued. We recorded an $18.7 million net credit loss on the exchange of bonds associated with our investment in the subordinated tax increment revenue bonds.

[2] These charges resulted from changes in management’s plans for these properties, primarily the marketing of these properties for sale. Also included in this caption are impairments associated with dispositions that did not qualify to be reported in discontinued operations.

[3] Amounts reported in 2012 are based on third party offers to buy our interests in industrial real estate joint ventures.

[4] Amounts reported in 2012 are based on third party offers.