TAXABLE INCOME AND TAX BASIS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
TAXABLE INCOME AND TAX BASIS
Excess amount of statement income over taxable income	$ 4,300,000
Excess amount of cumulative statement basis over cumulative taxable basis	4,800,000
Excess amount of statement income from joint venture investments over taxable income	1,300,000
Hamilton Green
TAXABLE INCOME AND TAX BASIS
Book/Tax differences from depreciation and amortization	1,100,000
Nashoba Apartments in Acton, Massachusetts
TAXABLE INCOME AND TAX BASIS
Book/Tax differences on tax free exchanges	$ 3,700,000