Dispositions, Assets Held for Sale and Discontinued Operations (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Rental income, disposed	$ 5,477	$ 12,166
Expenses:
Interest expense, disposed	851	2,262
Property operating expenses, disposed	1,362	1,527
Depreciation expense, disposed	820	3,256
Expenses, disposed	3,033	7,045
Income (loss) from disposed properties	$ 2,444	$ 5,121