RENTAL PROPERTIES (Details)	6 Months Ended
	Jun. 30, 2018 USD ($) property item	Dec. 31, 2017 USD ($)	Jun. 30, 2017 item
RENTAL PROPERTIES
Number of units | item			1,033
Rental properties
Total fixed assets	$ 347,951,931	$ 311,951,597
Less: Accumulated depreciation	(111,911,138)	(104,797,803)
Total fixed assets, net	236,040,793	207,153,794
Land, improvements and parking lots
Rental properties
Total fixed assets	$ 73,067,362	65,087,214
Land, improvements and parking lots | Minimum
Rental properties
Useful Life	15 years
Land, improvements and parking lots | Maximum
Rental properties
Useful Life	40 years
Buildings and improvements
Rental properties
Total fixed assets	$ 222,178,309	201,844,565
Buildings and improvements | Minimum
Rental properties
Useful Life	15 years
Buildings and improvements | Maximum
Rental properties
Useful Life	40 years
Kitchen cabinets
Rental properties
Total fixed assets	$ 14,163,255	12,338,627
Kitchen cabinets | Minimum
Rental properties
Useful Life	5 years
Kitchen cabinets | Maximum
Rental properties
Useful Life	10 years
Carpets
Rental properties
Total fixed assets	$ 10,246,486	8,802,831
Carpets | Minimum
Rental properties
Useful Life	5 years
Carpets | Maximum
Rental properties
Useful Life	10 years
Air conditioning
Rental properties
Total fixed assets	$ 641,079	641,079
Air conditioning | Minimum
Rental properties
Useful Life	5 years
Air conditioning | Maximum
Rental properties
Useful Life	10 years
Laundry equipment
Rental properties
Total fixed assets	$ 403,211	263,275
Laundry equipment | Minimum
Rental properties
Useful Life	5 years
Laundry equipment | Maximum
Rental properties
Useful Life	7 years
Elevators
Rental properties
Total fixed assets	$ 1,839,590	1,139,296
Elevators | Minimum
Rental properties
Useful Life	20 years
Elevators | Maximum
Rental properties
Useful Life	40 years
Swimming pools
Rental properties
Total fixed assets	$ 444,629	444,629
Swimming pools | Minimum
Rental properties
Useful Life	10 years
Swimming pools | Maximum
Rental properties
Useful Life	30 years
Equipment
Rental properties
Total fixed assets	$ 12,826,738	11,163,864
Equipment | Minimum
Rental properties
Useful Life	5 years
Equipment | Maximum
Rental properties
Useful Life	30 years
Motor vehicles
Rental properties
Total fixed assets	$ 216,260	216,260
Motor vehicles | Maximum
Rental properties
Useful Life	5 years
Fences
Rental properties
Total fixed assets	$ 43,099	37,465
Fences | Minimum
Rental properties
Useful Life	5 years
Fences | Maximum
Rental properties
Useful Life	15 years
Furniture and fixtures
Rental properties
Total fixed assets	$ 11,299,442	9,390,021
Furniture and fixtures | Minimum
Rental properties
Useful Life	5 years
Furniture and fixtures | Maximum
Rental properties
Useful Life	7 years
Smoke alarms
Rental properties
Total fixed assets	$ 582,471	$ 582,471
Smoke alarms | Minimum
Rental properties
Useful Life	5 years
Smoke alarms | Maximum
Rental properties
Useful Life	7 years
Wholly owned properties
RENTAL PROPERTIES
Number of properties | item	27
Investment Properties
RENTAL PROPERTIES
Number of units | property	1,033
Residential and mixed-use properties
RENTAL PROPERTIES
Number of units | item	2,711
Number of properties | item	23
Residential and mixed-use properties | Partially owned properties
RENTAL PROPERTIES
Number of units | item	701
Number of properties | item	8
Residential and mixed-use properties | Partially owned properties | Minimum
RENTAL PROPERTIES
Ownership interest (as a percent)	40.00%
Residential and mixed-use properties | Partially owned properties | Maximum
RENTAL PROPERTIES
Ownership interest (as a percent)	50.00%
Residential and mixed-use properties | Investment Properties | Partially owned properties
RENTAL PROPERTIES
Number of units | property	701
Condominium
RENTAL PROPERTIES
Number of units | item	19
Condominium | Wholly owned properties
RENTAL PROPERTIES
Number of units | item	19
Number of properties | item	1