Property (Schedule Of Property) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Land	$ 870,826	$ 918,627
Land held for development	126,616	124,528
Land under development	15,545	20,281
Buildings and improvements	3,267,219	3,557,173
Construction in-progress	65,685	67,917
Total	$ 4,345,891	$ 4,688,526

Gross amount, at the balance sheet date, of long-lived assets under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service.

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Carrying amount as of the balance sheet date, net of valuation allowances and impairment losses, of costs of land expected to be developed in the near term plus capitalized costs of development, for purposes of selling completed units to home buyers or commercial or industrial entities..

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Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

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Carrying amount as of the balance sheet date of real estate held for productive use. This excludes land held for sale.

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Carrying amount of land available for development.

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