INVESTMENT IN UNCONSOLIDATED JOINT VENTURES - Investment in Pacific Oak Opportunity Zone Fund I (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) property	Sep. 30, 2020 USD ($) property	Dec. 31, 2019 USD ($) unit
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 69,686	$ 69,686	$ 78,276
Pacific Oak Opportunity Zone Fund I
Schedule of Equity Method Investments [Line Items]
Number of units in real estate property | unit			91
Investments	20,900	20,900	$ 20,600
Investments in unconsolidated entities	$ 20,891	$ 20,891	20,846
Acquisition related costs			$ 200
Number of joint ventures with real estate under development | property	3	3
Loss from equity method investments	$ 600	$ 600