Mortgage and Other Indebtedness Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified									9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended
	Sep. 30, 2012 Pay Fixed Receive Variable Swap One [Member]	Sep. 30, 2012 Pay fixed receive variable swap Two [Member]	Sep. 30, 2012 Pay fixed receive variable swap Three [Member]	Sep. 30, 2012 Pay fixed receive variable swap Four [Member]	Sep. 30, 2012 Interest Rate Cap [Member]	Mar. 31, 2012 Interest Rate Cap [Member]	Sep. 30, 2012 Interest Rate Swap [Member]	Dec. 31, 2011 Interest Rate Swap [Member]	Sep. 30, 2012 Cash Flow Hedging [Member] Pay Fixed Receive Variable Swap One [Member] Accrued Liabilities [Member]	Dec. 31, 2011 Cash Flow Hedging [Member] Pay Fixed Receive Variable Swap One [Member] Accrued Liabilities [Member]	Sep. 30, 2012 Cash Flow Hedging [Member] Pay fixed receive variable swap Two [Member] Accrued Liabilities [Member]	Dec. 31, 2011 Cash Flow Hedging [Member] Pay fixed receive variable swap Two [Member] Accrued Liabilities [Member]	Sep. 30, 2012 Cash Flow Hedging [Member] Pay fixed receive variable swap Three [Member] Accrued Liabilities [Member]	Dec. 31, 2011 Cash Flow Hedging [Member] Pay fixed receive variable swap Three [Member] Accrued Liabilities [Member]	Sep. 30, 2012 Cash Flow Hedging [Member] Pay fixed receive variable swap Four [Member] Accrued Liabilities [Member]	Dec. 31, 2011 Cash Flow Hedging [Member] Pay fixed receive variable swap Four [Member] Accrued Liabilities [Member]	Sep. 30, 2012 Cash Flow Hedging [Member] Interest Rate Cap [Member] Intangible lease assets and other assets [Member]	Dec. 31, 2011 Cash Flow Hedging [Member] Interest Rate Cap [Member] Intangible lease assets and other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative, Number of Instruments Held					1		4
Notional Amount of Interest Rate Derivatives	$ 55,541	$ 34,770	$ 13,001	$ 11,572	$ 124,250	$ 125,000	$ 114,884	$ 117,700
Derivative, Description of Variable Rate Basis									1-month LIBOR		1-month LIBOR		1-month LIBOR		1-month LIBOR		3-month LIBOR
Derivative, Basis Spread on Variable Rate									2.149%		2.187%		2.142%		2.236%		5.00%
Interest Rate Derivatives, at Fair Value, Net									(3,018)	(2,674)	(1,930)	(1,725)	(704)	(622)	(660)	(596)	0	0
Derivative, Maturity Date									Apr. 30, 2016		Apr. 30, 2016		Apr. 30, 2016		Apr. 30, 2016		Jan. 01, 2014
Amortized amount	$ 48,337	$ 30,276	$ 11,313	$ 10,083	$ 122,375
Debt Instrument, Number of Instruments					1		4