Real Estate Investments - Discontinued Operations and Assets Held for Sale - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Rental income	$ 98,740	$ 95,034
Expenses
Property operating	35,406	34,263
Bad debts, net of recoveries	(39)	(207)
Other Income (Expense)
Interest and other income, net	86	91
Discontinued Operations
Income from discontinued operations	(7)	333
INCOME (LOSS) FROM DISCONTINUED OPERATIONS	(7)	333
Discontinued Operations [Member]
Revenues
Rental income	0	341
Revenues	0	341
Expenses
Property operating	7	29
Bad debts, net of recoveries	0	(1)
Total Expenses	7	28
Other Income (Expense)
Interest and other income, net	0	20
Total other income (expense)	0	20
Discontinued Operations
Income from discontinued operations	(7)	333
INCOME (LOSS) FROM DISCONTINUED OPERATIONS	$ (7)	$ 333