FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Carrying Amount
Liabilities:
Mortgages payable	$ 414,672	$ 530,793
Junior subordinated notes	25,093	25,055
Carrying Amount | Loans receivable subject to credit risk
Assets:
Loans receivable	46,276	43,623
Carrying Amount | SBA 7(a) loans receivable, subject to secured borrowings
Assets:
Loans receivable	24,162	29,524
Carrying Amount | Other loans receivable
Assets:
Loans receivable	1,356	2,593
Fair Value, Measurements, Nonrecurring | Estimated Fair Value | Level 3
Liabilities:
Mortgages payable	417,912	516,892
Junior subordinated notes	25,490	25,173
Fair Value, Measurements, Nonrecurring | Estimated Fair Value | Level 3 | Loans receivable subject to credit risk
Assets:
Loans receivable	46,176	43,621
Fair Value, Measurements, Nonrecurring | Estimated Fair Value | Level 3 | SBA 7(a) loans receivable, subject to secured borrowings
Assets:
Loans receivable	24,607	29,976
Fair Value, Measurements, Nonrecurring | Estimated Fair Value | Level 3 | Other loans receivable
Assets:
Loans receivable	$ 1,297	$ 2,550