Condensed Consolidated Balance Sheet (Unaudited) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Real estate investments, net:
Operating properties, net	$ 1,774,259,000	$ 1,772,923,000
Properties classified as held for sale, net	24,540,000	24,540,000
Total real estate investments, net	1,798,799,000	1,797,463,000
Real estate notes receivable, net	58,264,000	57,091,000
Cash and cash equivalents	154,287,000	29,270,000
Accounts and other receivables, net	13,190,000	16,385,000
Restricted cash and escrow deposits	15,106,000	26,679,000
Identified intangible assets, net	286,957,000	300,587,000
Non-real estate assets of properties held for sale	3,768,000	3,768,000
Other assets, net	49,957,000	40,552,000
Total assets	2,380,328,000	2,271,795,000
Liabilities:
Mortgage and secured term loans payable, net	667,540,000	699,526,000
Outstanding balance on unsecured revolving credit facility	0	7,000,000
Accounts payable and accrued liabilities	46,509,000	43,033,000
Derivative financial instruments - interest rate swaps	1,685,000	1,527,000
Security deposits, prepaid rent and other liabilities	19,750,000	16,168,000
Identified intangible liabilities, net	12,307,000	13,059,000
Liabilities of properties held for sale	369,000	369,000
Total liabilities	748,160,000	780,682,000
Commitments and contingencies (Note 11)
Redeemable noncontrolling interest of limited partners	3,775,000	3,867,000
Stockholders' equity:
Preferred stock, $0.01 par value; 200,000,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.01 par value; 1,000,000,000 shares authorized; 226,511,511 and 202,643,705 shares issued and outstanding as of June 30, 2011 and December 31, 2010, respectively	2,267,000	2,026,000
Additional paid-in capital	2,012,448,000	1,795,413,000
Accumulated deficit	(386,322,000)	(310,193,000)
Total stockholders' equity	1,628,393,000	1,487,246,000
Total liabilities and equity	$ 2,380,328,000	$ 2,271,795,000