MORTGAGE LOANS AND NOTES PAYABLE - Future Payments (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Future principal payment requirements on the outstanding mortgage loans and notes payable at year end    
Less: Loan procurement costs, net $ (1,709) $ (2,150)
Total mortgage indebtedness 112,214 114,618
Mortgages    
Future principal payment requirements on the outstanding mortgage loans and notes payable at year end    
2017 644  
2018 2,650  
2019 11,652  
2020 12,791  
2021 45,057  
2022 and thereafter 36,645  
Total mortgage payments 109,439 111,586
Plus: Unamortized fair value adjustment 3,472 3,742
Less: Loan procurement costs, net (697) (710)
Total mortgage indebtedness $ 112,214 $ 114,618