SIGNIFICANT ACCOUNTING POLICIES (Details)		6 Months Ended
	Jan. 03, 2012	Jun. 30, 2018 USD ($) item shares	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)	Aug. 20, 2007
Principles of Consolidation
Value at which partnership investments discontinue use of equity method		$ 0
Amount of legal obligations related to investments no longer classified as equity method		$ 0
Revenue Recognition
Period for which arrears are charged against income		60 days
Deferred Financing Costs
Amortization of deferred financing costs		$ 106,000	$ 94,000
Income Taxes
Provision for income taxes		$ 0
Segment Reporting
Number of segments | item		1
Income Per Unit
Dilutive units | shares		0
Concentration of Credit Risks and Financial Instruments
Federally uninsured amounts of cash and cash equivalents, and security deposits included in prepaid expenses and other assets		$ 11,735,000			$ 8,898,000
Advertising Expense
Advertising expense		$ 99,782	98,811
Interest Capitalized
Capitalized interest			$ 0	$ 0
Minimum
Principles of Consolidation
Ownership interest in each subsidiary (as a percent)		99.67%
Interest Capitalized
Criteria of capitalization of interest on property based on specified period of construction		1 year
Minimum | Cash and cash equivalents
Concentration of Credit Risks and Financial Instruments
Interest rate on interest bearing accounts (as a percent)		0.01%
Maximum
Principles of Consolidation
Ownership interest in each subsidiary (as a percent)		100.00%
Maximum | Cash and cash equivalents
Concentration of Credit Risks and Financial Instruments
Interest rate on interest bearing accounts (as a percent)		0.20%
Investment Properties
Principles of Consolidation
Number of limited liability companies/partnerships | item		8
Investment Properties | Minimum
Principles of Consolidation
Percentage of ownership interest		40.00%
Investment Properties | Maximum
Principles of Consolidation
Percentage of ownership interest		50.00%
Class A
Income (Loss) Per Depositary Receipt
Forward split of depositary receipts	3
Exchange ratio of depositary receipts for partnership units before adjustment	10
Exchange ratio of depositary receipts for partnership units after adjustment	30
Number of units in each depository receipt	0.03333					0.1