REAL ESTATE PROPERTIES - Summary of Activity (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Real Estate Properties
Balance at the beginning of the period				$ 169,689					$ 169,689
Improvements									887
Depreciation	$ (1,595)	$ (1,777)	$ (1,809)	(1,561)	$ (1,568)	$ (1,373)	$ (1,428)	$ (1,547)	(6,742)	$ (5,916)
Impairment Charge									(3,642)
Balance at the end of the period	160,192				169,689				160,192	169,689
Multi-family residential
Real Estate Properties
Balance at the beginning of the period				159,434					159,434
Improvements									802
Depreciation									(6,632)
Impairment Charge									0
Balance at the end of the period	153,604				159,434				153,604	159,434
Land
Real Estate Properties
Impairment Charge									(3,642)
Land | Daytona, FL
Real Estate Properties
Balance at the beginning of the period				8,021					8,021
Improvements									0
Depreciation									0
Impairment Charge									(3,642)
Balance at the end of the period	4,379				8,021				4,379	8,021
Shopping centers/retail | Newark Joint Venture
Real Estate Properties
Impairment Charge									0
Shopping centers/retail | Yonkers, NY.  | Newark Joint Venture
Real Estate Properties
Balance at the beginning of the period				$ 2,234					2,234
Improvements									85
Depreciation									(110)
Impairment Charge									0
Balance at the end of the period	$ 2,209				$ 2,234				$ 2,209	$ 2,234