SIGNIFICANT ACCOUNTING POLICIES (Financial Instruments Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Development property investments	$ 302,245	$ 228,233
Bridge loan investments, Fair Value	79,581
Operating property loans	5,862	5,938
Total investments	387,688	234,171
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Development property investments	302,245	228,233
Bridge loan investments, Fair Value	79,581
Operating property loans	5,862	5,938
Total investments	$ 387,688	$ 234,171