Consolidated Statements of Operations (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Revenues:
Rental income	$ 69,935,000	$ 69,243,000
Interest income from mortgage notes receivable and other income	1,308,000	1,649,000
Total revenues	71,243,000	70,892,000
Expenses:
Rental expenses	22,716,000	23,858,000
General and administrative expenses	8,150,000	7,308,000
Acquisition-related expenses (Note 3)	2,321,000	1,062,000
Depreciation and amortization	27,357,000	26,750,000
Total expenses	60,544,000	58,978,000
Income before other income (expense)	10,699,000	11,914,000
Interest expense (including amortization of deferred financing costs and debt premium/discount):
Interest expense related to mortgage loan payables and credit facility	(10,233,000)	(9,986,000)
Interest expense related to derivative financial instruments and net change in fair value of derivative financial instruments	(800,000)	144,000
Interest and dividend income	27,000	118,000
Net (loss) income	(307,000)	2,190,000
Less: Net income attributable to noncontrolling interest of limited partners	(8,000)	(40,000)
Net (loss) income attributable to controlling interest	$ (315,000)	$ 2,150,000
Net (loss) income per share attributable to controlling interest on distributed and undistributed earnings - basic	$ 0.00	$ 0.01
Net (loss) income per share attributable to controlling interest on distributed and undistributed earnings - diluted	$ 0.00	$ 0.01
Weighted average number of shares outstanding
Basic	228,881,454	214,797,450
Diluted	228,881,454	214,996,502