MORTGAGE NOTES PAYABLE (Details) (USD $)		6 Months Ended		0 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Mortgages payable	Jun. 30, 2013 Mortgages payable Boylston Street, Westgate Woburn, School Street and Cypress Street	Feb. 25, 2013 Mortgages payable Hamilton Cypress LLC Commercial-1031Exchange Brookline, Massachusetts	Mar. 11, 2013 Mortgages payable Property located at School Street	Jun. 30, 2013 Mortgages payable Minimum	Jun. 30, 2013 Mortgages payable Maximum
MORTGAGE NOTES PAYABLE
Interest rate (as a percent)					3.70%	3.25%	7.07%
Amount of monthly installments including principal		$ 656,000
Weighted average interest rate (as a percent)		5.30%
Effective interest rate (as a percent)	5.47%	5.40%
Annual maturities of mortgage debt
2014-current maturities	27,517,000
2015	9,160,000
2016	267,000
2017	486,000
2018	1,709,000
Thereafter	92,532,000
Total	131,671,000
Additional disclosures related to mortgages
Amount of mortgage paid off				3,697,000
Mortgage prepayment penalties				0
Increase in debt			28,000,000
Amount of new loan					15,000,000
Period of interest only payments on loans					3 years
Deferred financing cost associated with mortgage			67,000		159,000
Total amount expected to be refinanced			27,000,000
Expected amount of new loan			55,000,000
Expected prepayment penalties upon refinancing			$ 125,000