Dispositions, Assets Held for Sale and Discontinued Operations (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues:
Rental income, disposed	$ 3,636,000	$ 5,002,000	$ 8,677,000	$ 10,002,000
Expenses:
Interest expense, disposed	549,000	1,403,000	1,947,000	2,797,000
Property operating expenses, disposed	650,000	568,000	1,205,000	1,080,000
Depreciation expense, disposed	1,070,000	1,486,000	2,560,000	2,970,000
Expenses, disposed	2,269,000	3,457,000	5,712,000	6,847,000
Income (loss) from disposed properties	$ 1,367,000	$ 1,545,000	$ 2,965,000	$ 3,155,000