Mortgage and Other Indebtedness, Derivative Instrument Risk (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in OCI/L (Effective Portion)				$ 1,515
Loss Recognized in Earnings (Effective Portion)				(1,884)
Gain Recognized in Earnings (Ineffective Portion)	0	8	0	16
Reclassification of losses currently reported in accumulated other comprehensive income to interest expense in the next twelve months	2,382		2,382
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in OCI/L (Effective Portion)	(2,634)	906	(2,072)
Loss Recognized in Earnings (Effective Portion)	$ (636)	$ (941)	$ (658)