MORTGAGE NOTES PAYABLE (Details) (USD $)		12 Months Ended	1 Months Ended		1 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Mortgages payable	Jul. 31, 2011 Mortgages payable Battle Green Apartments	Jul. 27, 2011 Mortgages payable Battle Green Apartments	Jun. 30, 2011 Mortgages payable Battle Green Apartments Harold Brown	Jun. 02, 2011 Mortgages payable Battle Green Apartments Harold Brown	Dec. 31, 2012 Mortgages payable Boylston Street, Westgate Woburn, School Street and Cypress Street
MORTGAGE NOTES PAYABLE
Interest rate (as a percent)				4.95%		6.00%
Amount of monthly installments including principal		$ 742,000
Effective interest rate (as a percent)	5.65%	5.63%		5.07%
Weighted average interest rate (as a percent)		5.53%
Annual maturities of mortgage debt
2013-current maturities	41,275,000
2014	14,669,000
2015	2,184,000
2016	194,000
2017	205,000
Thereafter	79,529,000
Total	138,056,000
Additional disclosures related to mortgages
Borrowings			5,000,000		3,998,573
Amortization period of debt			30 years
Deferred financing cost associated with mortgage				100,000			353,000
Total amount expected to be refinanced							47,000,000
Expected prepayment penalties upon refinancing							$ 250,000