Impairment (Schedule Of Impairment Charges)(Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Asset Impairment [Line Items]
Other	$ 0		$ 0		$ 165		$ 0
Total reported in continuing operations	2,358		197		2,579		9,585
Total impairment charges	2,358		336		2,815		15,410
Equity in earnings of real estate joint ventures and partnerships, net	5,125		4,905		14,467		(6,715)
Net impact of impairment charges	2,387		393		3,210		35,356
Land Held For Development And Undeveloped Land [Member]
Asset Impairment [Line Items]
Impairment losses related to property	2,358	[1]	0	[1]	2,358	[1]	0	[1]
Property Marketed For Sale Or Sold [Member]
Asset Impairment [Line Items]
Impairment losses related to property	0	[2]	197	[2]	56	[2]	2,977	[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]	0	[3]	6,608	[3]
Property Held For Sale Or Sold [Member]
Asset Impairment [Line Items]
Impairment losses related to property	0	[4]	139	[4]	236	[4]	5,825	[4]
Impairment Charges On Equity In Earnings Of Real Estate Joint Ventures And Partnerships, Net [Member]
Asset Impairment [Line Items]
Equity in earnings of real estate joint ventures and partnerships, net	$ 29		$ 57		$ 395		$ 19,946

[1] Impairment was prompted by changes in management's plans for these properties, recent comparable market transactions and/or a change in market conditions.

[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 were based on third party offers to buy our interests in industrial real estate joint ventures.

[4] Amounts reported were based on third party offers.