SUBSEQUENT EVENTS (Details)				2 Months Ended	12 Months Ended			100 Months Ended
	Jan. 15, 2016 USD ($)	Jan. 07, 2016 USD ($) item	Jul. 31, 2014	Mar. 10, 2016 USD ($) $ / item shares	Dec. 31, 2015 USD ($) $ / item shares	Dec. 31, 2014 USD ($) $ / item shares	Dec. 31, 2013 USD ($) shares	Dec. 31, 2015 USD ($) $ / item shares	Sep. 18, 2015 item
Subsequent events
Total cost of repurchase					$ 3,429,953	$ 2,685,583	$ 1,094,609	$ 38,596,000
Units repurchased (in shares) | shares					(2,279)	(1,834)	(957)
Line of credit balance					$ 25,000,000			$ 25,000,000
General Partnership
Subsequent events
Repurchase price of units (in dollars per unit) | $ / item								877.14
Total cost of repurchase					$ 33,878	$ 26,363	$ 10,849
Subsequent event | General Partnership
Subsequent events
Total cost of repurchase				$ 6,783
Subsequent event | Line of Credit
Subsequent events
Line of credit balance	$ 0
Payment on line of credit	$ 2,000,000	$ 23,000,000
Class A
Subsequent events
Repurchase price of depository receipts (in dollars per receipt) | $ / item					49.55	47.90		26.63
Repurchase price of units (in dollars per unit) | $ / item					1,486.50	1,437		798.90
Class A | Limited Partner
Subsequent events
Total cost of repurchase					$ 2,752,393	$ 2,158,332	877,623
Class A | Subsequent event
Subsequent events
Repurchase price of depository receipts (in dollars per receipt) | $ / item				50.11
Repurchase price of units (in dollars per unit) | $ / item				1,503.26
Class A | Subsequent event | Limited Partner
Subsequent events
Total cost of repurchase				$ 558,722
Class B
Subsequent events
Repurchase price of units (in dollars per unit) | $ / item								877.14
Class B | Limited Partner
Subsequent events
Total cost of repurchase					$ 643,682	$ 500,888	$ 206,137
Class B | Subsequent event | Limited Partner
Subsequent events
Total cost of repurchase				$ 128,874
LIBOR | Line of Credit
Subsequent events
Reference rate			one month LIBOR
Residences at CaptainParkers LLC Residential Apartments Lexington, Massachusetts
Subsequent events
Number of units | item		94							94
Residences at CaptainParkers LLC Residential Apartments Lexington, Massachusetts | Subsequent event | Term Loan, Due February 2026
Subsequent events
Principal amount		$ 20,071,000
Residences at CaptainParkers LLC Residential Apartments Lexington, Massachusetts | LIBOR | Subsequent event | Term Loan, Due February 2026
Subsequent events
Reference rate		one month LIBOR
Margin over basis of interest rate (as a percent)		2.01%
Treasury Units
Subsequent events
Units repurchased (in shares) | shares					2,279	1,834	957
Treasury Units | General Partnership
Subsequent events
Units repurchased (in shares) | shares					23	18		152
Treasury Units | Subsequent event | General Partnership
Subsequent events
Units repurchased (in shares) | shares				5
Treasury Units | Class A | Limited Partner
Subsequent events
Number of depository receipts repurchased | shares					54,682	44,025		1,341,598
Treasury Units | Class A | Subsequent event | Limited Partner
Subsequent events
Number of depository receipts repurchased | shares				10,829
Treasury Units | Class B | Limited Partner
Subsequent events
Units repurchased (in shares) | shares					433	349		2,885
Treasury Units | Class B | Subsequent event | Limited Partner
Subsequent events
Units repurchased (in shares) | shares				86