Segment Reporting (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting [Abstract]
Rental income from real estate assets sold or held for sale	$ 4,006	$ 16,280	$ 24,747	$ 54,803
Operating expenses from real estate assets sold or held for sale	(1,461)	(5,940)	(8,834)	(19,641)
Net operating income from real estate assets sold or held for sale	$ 2,545	$ 10,340	$ 15,913	$ 35,162