Mortgage and Other Indebtedness, Derivative Instrument Risk (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in Earnings (Ineffective Portion)	$ 0	$ 7	$ 0	$ 23
Reclassification of losses currently reported in accumulated other comprehensive income to interest expense in the next twelve months	5,456		5,456
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in OCI/L (Effective Portion)	(3,393)	1,054	(5,466)	2,569
Loss Recognized in Earnings (Effective Portion)	$ (668)	$ (889)	$ (1,326)	$ (2,773)

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The portion of gains on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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The effective portion of gains on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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The portion of losses on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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