SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Millions	Oct. 05, 2020 USD ($) property joint_venture investment $ / shares shares	Sep. 30, 2020 investment property $ / shares	Feb. 19, 2020	Dec. 31, 2019 $ / shares
Subsequent Event [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01		$ 0.01
Number of investments in equity securities | investment		3
Number of investments in unconsolidated joint venture | investment		6
Office Properties
Subsequent Event [Line Items]
Number of real estate properties		6
POSOR II
Subsequent Event [Line Items]
Merger, common stock conversion ratio			96.43%
Subsequent Event
Subsequent Event [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Conversion of stock, shares issued (in shares) | shares	28,973,906
Subsequent Event | POSOR II
Subsequent Event [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Merger, common stock conversion ratio	96.43%
Number of consolidated joint ventures | joint_venture	1
Number of investments in equity securities | investment	2
Number of investments in unconsolidated joint venture | investment	2
Loans assumed | $	$ 331.8
Subsequent Event | POSOR II | Hotel
Subsequent Event [Line Items]
Number of real estate properties	2
Subsequent Event | POSOR II | Office Properties
Subsequent Event [Line Items]
Number of real estate properties	3
Subsequent Event | POSOR II | Apartment Building
Subsequent Event [Line Items]
Number of real estate properties	1
Subsequent Event | POSOR II | Office/ Retail Property
Subsequent Event [Line Items]
Number of real estate properties	1