Segment Reporting (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Rental income from real estate assets sold or held for sale	$ 3,225	$ 12,706
Operating expenses from real estate assets sold or held for sale	(1,081)	(4,605)
Net operating income from real estate assets sold or held for sale	$ 2,144	$ 8,101