Preferred Equity Investments and Investments in Unconsolidated Real Estate Joint Ventures (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Balance Sheets:
Real estate, net of depreciation	$ 497,715		$ 497,715		$ 399,111
Other assets	73,062		73,062		62,667
Total assets	570,777		570,777		461,778
Mortgage payable	430,416		430,416		325,702
Other liabilities	27,349		27,349		25,956
Total liabilities	457,765		457,765		351,658
Members' equity	113,012		113,012		110,120
Total liabilities and members' equity	570,777		570,777		$ 461,778
Operating Statement:
Rental revenues	4,217	$ 767	7,591	$ 1,586
Operating expenses	(3,461)	(920)	(6,247)	(1,417)
Income (loss) before debt service and depreciation and amortization	756	(153)	1,344	169
Interest expense, net	(1,808)	(561)	(3,359)	(875)
Depreciation and amortization	(2,194)	(618)	(4,130)	(959)
Net loss	$ (3,246)	$ (1,332)	$ (6,145)	$ (1,665)