SUBSEQUENT EVENTS (Details)				1 Months Ended	12 Months Ended			113 Months Ended
	Mar. 01, 2017 USD ($)	Jan. 07, 2016	Jul. 31, 2014	Feb. 28, 2014 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2016 USD ($) $ / item shares	Mar. 10, 2015 shares	Aug. 20, 2007 shares
Subsequent events
Number of depository receipts repurchased | shares								1,364,757
Repurchase price of depository receipts (in dollars per receipt) | $ / item								27.12
Payment on line of credit					$ 25,000,000
Notes Payable						$ 25,000,000
Repurchase of units | shares					965	2,279	1,834
Total cost of repurchase					$ 1,634,945	$ 3,429,953	$ 2,685,583	$ 40,231,000
Depository receipts authorized to be repurchased | shares									2,000,000	300,000
Residences at Captain Parkers LLC Residential Apartments Lexington, Massachusetts | LIBOR
Subsequent events
Debt Instrument, Basis Spread on Variable Rate		2.01%
Mortgages payable | Linhart L.P. Residential/Commercial Newton, Massachusetts
Subsequent events
Amount of mortgage paid off				$ 1,926,000
Mortgages payable | Hamilton Linewt LLC Commercial-1031 Exchange Newton, Massachusetts
Subsequent events
Amount of mortgage paid off				$ 1,466,000
Line of Credit | LIBOR
Subsequent events
Debt Instrument Description of Variable Rate Basis Used for Calculation of Base Rate			one month LIBOR
Subsequent event | Hamilton Bay Apts
Subsequent events
Amount of mortgage paid off	$ 4,444,918
Capital contributions	$ 2,222,000
General Partnership
Subsequent events
Number of depository receipts repurchased | shares								162
Total cost of repurchase					16,181	33,878	26,363
Class B
Subsequent events
Number of depository receipts repurchased | shares								3,068
Total cost of repurchase					$ 307,436	$ 643,682	$ 500,888