Summary of Significant Accounting Policies and Procedures and Recent Accounting Pronouncements (Details) (USD $)	Sep. 30, 2011	Aug. 31, 2011	Jul. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies and Procedures and Recent Accounting Pronouncements [Abstract]
Allowance for doubtful accounts	$ 1,400,000			$ 1,100,000
Other assets [Abstract]
Value of in-place and above market leases, net	150,124,000			26,221,000
Deferred bond financing costs, net	22,729,000			14,203,000
Notes receivable issued in connection with Crest property sales	21,965,000			22,075,000
Note receivable assumed in connection with 2011 acquisition	8,780,000			0
Prepaid expenses	8,236,000			8,431,000
Restricted escrow deposits	2,830,000			6,361,000
Credit facility origination costs, net	3,508,000			4,619,000
Deferred financing costs on assumed mortgages payable, net	835,000			0
Corporate assets, net of accumulated depreciation and amortization	739,000			827,000
Other items	2,138,000			1,861,000
Other assets	221,884,000			84,598,000
Distributions payable [Abstract]
Distributions payable	21,360,000			19,051,000
Accounts payable and accrued expenses [Abstract]
Bond interest payable	12,925,000			33,240,000
Accrued costs on properties under development	5,023,000			420,000
Other items	16,590,000			13,359,000
Accounts payable and accrued expenses	34,538,000			47,019,000
Other liabilities disclosure [Abstract]
Rent received in advance	17,496,000			14,564,000
Value of in-place below-market leases, net	6,600,000			3,452,000
Security deposits	4,488,000			4,539,000
Other liabilities	28,584,000			22,555,000
Par value change [Abstract]
Par value of common and preferred stock	$ 0.01	$ 0.01	$ 1.00	$ 1.00
Common Stock [Member]
Distributions payable [Abstract]
Distributions payable	19,339,000			17,030,000
Preferred Stock [Member]
Distributions payable [Abstract]
Distributions payable	$ 2,021,000			$ 2,021,000