SIGNIFICANT ACCOUNTING POLICIES (Details)			12 Months Ended
	Jan. 03, 2012	Jan. 03, 2012	Dec. 31, 2018 USD ($) tenant item shares	Dec. 31, 2017 USD ($) tenant	Dec. 31, 2016 USD ($) tenant
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			$ 216,000	$ 193,000	$ 188,000
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
Single tenants | tenant			0	0	0
Federally uninsured amounts of cash and cash equivalents, and security deposits included in prepaid expenses and other assets			$ 10,784,000	$ 8,898,000
Advertising Expense
Advertising expense			226,523	201,040	$ 191,815
Interest Capitalized
Capitalized interest			$ 0	$ 0	$ 0
Minimum
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 | Cash and cash equivalents
Concentration of Credit Risks and Financial Instruments
Interest rate on interest bearing accounts (as a percent)			1.61%
Less Than Wholly Owned Subsidiaries [Member] | Minimum
Principles of Consolidation
Ownership interest in each subsidiary (as a percent)			99.67%
Less Than Wholly Owned Subsidiaries [Member] | Maximum
Principles of Consolidation
Ownership interest in each subsidiary (as a percent)			100.00%
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	10
Exchange ratio of depositary receipts for partnership units after adjustment	30	30
Number of units in each depository receipt	0.03333	0.03333