INVESTMENT IN AND ADVANCES TO UNCONSOLIDATED JOINT VENTURES - Additional Information (Details)	1 Months Ended	12 Months Ended
	Apr. 30, 2012	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 22, 2013
Schedule of Equity Method Investments [Line Items]
Distributions from operations of investment in unconsolidated joint ventures		$ 3,317,000	$ 1,250,000	$ 0
Income (expenses) from investment		$ (14,930,000)	(13,381,000)	(15,291,000)
Grace Lake JV, LLC
Schedule of Equity Method Investments [Line Items]
Percentage of equity kicker received with right to convert upon capital event	25.00%
Preferred return used to determine distribution of excess cash flow		8.25%
Percentage of distribution of all excess cash flows and all disposition proceeds upon any sale entitled after consideration of preferred return and return of equity remaining in the property to operating partner		25.00%
Percentage of investment of operating partner		81.00%
Distributions from operations of investment in unconsolidated joint ventures		$ 3,300,000	1,300,000
Grace Lake JV, LLC | LP Units
Schedule of Equity Method Investments [Line Items]
Ownership interest						19.00%
Grace Lake JV, LLC | Limited liability company
Schedule of Equity Method Investments [Line Items]
Ownership interest		19.00%
24 Second Avenue Holdings LLC
Schedule of Equity Method Investments [Line Items]
Income (expenses) from investment		$ 2,400,000	(900,000)	(1,100,000)
Interest costs capitalized		$ 100,000	$ 1,500,000	$ 1,300,000
24 Second Avenue Holdings LLC | Apartment Building
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property		30
24 Second Avenue Holdings LLC | Apartment Building | Real Estate Property Sold
Schedule of Equity Method Investments [Line Items]
Number of real estate properties, under contract | property		19
Real estate properties, under contract		$ 49,600,000
24 Second Avenue Holdings LLC | Other
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property		1
24 Second Avenue Holdings LLC | Mezzanine Loan
Schedule of Equity Method Investments [Line Items]
Committed amount on credit agreement					$ 6,500,000
24 Second Avenue Holdings LLC | Co-venturer
Schedule of Equity Method Investments [Line Items]
Loans payable outstanding from unconsolidated joint venture		$ 11,300,000
24 Second Avenue Holdings LLC | Co-venturer | Construction Loan
Schedule of Equity Method Investments [Line Items]
Common equity interest					35,000,000.0
Preferred equity position					35,000,000.0
Loan refinance					50,400,000
Committed amount on credit agreement					$ 48,100,000
Remaining capital commitment to operating partner		$ 0