REAL ESTATE HELD FOR INVESTMENT (Narrative) (Details) ft² in Millions	Mar. 31, 2018 ft² property
Real Estate Properties [Line Items]
Occupancy	82.00%
Office Properties
Real Estate Properties [Line Items]
Number of real estate properties	8
Office Buildings, Campus
Real Estate Properties [Line Items]
Number of real estate properties	8
Rentable square feet | ft²	4.6
Office Buildings, Campus | Excluding Held-for-sale
Real Estate Properties [Line Items]
Number of real estate properties	6