SUBSEQUENT EVENTS (Details 2) (USD $)	3 Months Ended								12 Months Ended				12 Months Ended		0 Months Ended					12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Historical	Dec. 31, 2012 Subsequent event item	Feb. 25, 2013 Subsequent event Mortgage Notes Payable Hamilton Cypress LLC Commercial-1031Exchange Brookline, Massachusetts	Mar. 11, 2013 Subsequent event Mortgage Notes Payable Property located at School Street	Mar. 11, 2013 Subsequent event Mortgage Notes Payable Boylston Downtown LP and Westgate Apartments LLC	Mar. 22, 2013 Subsequent event Mortgage Notes Payable Boylston Downtown	Mar. 22, 2013 Subsequent event Mortgage Notes Payable Westgate Apartments LLC	Dec. 31, 2012 Pro Forma	Dec. 31, 2012 Pro Forma Adjustments Refinancing
SUBSEQUENT EVENTS
Amount of mortgage paid off															$ 3,697,000
Amount of new loan																15,000,000
Interest rate (as a percent)																3.70%
Period of interest on loans																3 years
Deferred financing cost associated with mortgage																159,000
Total amount expected to be refinanced																	28,000,000	19,500,000	7,932,000
Additional debt that entity can borrow																	29,000,000
Change in mortgage debt related to number of mortgaged properties														4
Expected amount of new loan																		40,000,000	17,000,000
ASSETS
Rental Properties	95,435,850				98,924,534				95,435,850	98,924,534			95,435,850							95,435,850
Cash and Cash Equivalents	6,981,906				4,050,157				6,981,906	4,050,157	3,245,361	2,879,663	6,981,906							28,447,599	21,465,693
Rents Receivable	475,083				434,252				475,083	434,252			475,083							475,083
Real Estate Tax Escrows	449,652				401,325				449,652	401,325			449,652							449,652
Prepaid Expenses and Other Assets	3,073,890				3,866,652				3,073,890	3,866,652			3,073,890							5,102,290	2,028,400
Investments in Unconsolidated Joint Ventures	13,986,173				16,780,657				13,986,173	16,780,657			13,986,173							13,986,173
Financing and Leasing Fees	1,135,936				919,187				1,135,936	919,187			1,135,936							2,581,731	1,445,795
Total Assets	121,538,490				125,376,764				121,538,490	125,376,764			121,538,490							146,478,378	24,939,888
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	138,055,522				139,161,612				138,055,522	139,161,612			138,055,522							163,035,536	24,980,014
Accounts Payable and Accrued Expenses	2,361,942				2,253,696				2,361,942	2,253,696			2,361,942							2,361,942
Advance Rental Payments and Security Deposits	3,636,704				3,603,708				3,636,704	3,603,708			3,636,704							3,636,704
Total Liabilities	144,054,168				146,687,616				144,054,168	146,687,616			144,054,168							169,034,182	24,980,014
Partners' Capital 130,444 units outstanding in 2012	(22,515,677)				(21,310,851)				(22,515,677)	(21,310,851)	(26,920,566)	(21,332,823)	(22,515,678)							(22,555,804)	(40,126)
Total Liabilities and Partners' Capital	121,538,490				125,376,764				121,538,490	125,376,764			121,538,490							146,478,378	24,939,888
Partners' Capital, units outstanding	130,444				131,484				130,444	131,484	131,484	132,346								130,444
Revenues
Rental income									35,244,008	33,608,799	31,816,175		35,244,008							35,244,008
Laundry and sundry income									388,401	426,803	439,782		388,401							388,401
Total Revenues	9,104,015	8,875,596	8,800,416	8,852,382	8,760,538	8,648,526	8,345,643	8,280,894	35,632,409	34,035,602	32,255,957		35,632,409							35,632,409
Expenses
Administrative									1,825,951	1,707,408	1,772,599		1,825,951							1,825,951
Depreciation and amortization									6,092,725	5,910,746	5,531,509		6,092,725							6,205,673	112,948
Management fee									1,446,620	1,404,467	1,330,157		1,446,620							1,446,620
Operating									3,633,619	4,080,647	3,784,401		3,633,619							3,633,619
Renting									183,529	365,110	528,686		183,529							183,529
Repairs and maintenance									5,179,408	5,056,054	4,886,724		5,179,408							5,179,408
Taxes and insurance									4,348,492	4,146,554	4,082,588		4,348,492							4,348,492
Total Expenses	5,704,596	5,730,319	5,413,735	5,861,694	5,722,971	5,665,232	5,508,842	5,773,941	22,710,344	22,670,986	21,916,664		22,710,344							22,823,292	112,948
Income Before Other Income and Discontinued Operations	3,399,419	3,145,277	3,386,681	2,990,688	3,037,567	2,983,294	2,836,801	2,506,953	12,922,065	11,364,616	10,339,293		12,922,065							12,809,117	(112,948)
Other Income (Loss)
Interest income									2,216	3,861	5,932		2,216							2,216
Interest expense									(7,802,999)	(7,965,422)	(8,053,628)		(7,802,999)							(7,730,177)	72,822
(Loss) from investments in unconsolidated joint ventures									(1,487,484)	(1,913,800)	(3,869,996)		(1,487,484)							(1,487,484)
Other (loss)											(700)
Total Other Income (Expense)	(2,214,288)	(2,370,824)	(2,339,420)	(2,363,735)	(2,469,002)	(2,523,314)	(2,480,305)	(2,402,740)	(9,288,267)	(9,875,361)	(11,918,392)		(9,288,267)							(9,215,445)	72,822
Income (loss) from Continuing Operations									3,633,798	1,489,255	(1,579,099)		3,633,798							3,593,672	(40,126)
Discontinued Operations
Income from discontinued operations										81,567	219,867
(Gain) on sale of real estate from discontinued operations										(7,720,459)
Total Discontinued Operations					(308)	(3,054)	7,736,789	68,599		7,802,026	219,867
Net Income (loss)	$ 1,185,131	$ 774,453	$ 1,047,261	$ 626,953	$ 568,257	$ 456,926	$ 8,093,285	$ 172,812	$ 3,633,798	$ 9,291,281	$ (1,359,232)		$ 3,633,798							$ 3,593,672	$ (40,126)
Income (loss) per Unit
Income (loss) before discontinued operations (in dollars per unit)	$ 9.07	$ 5.90	$ 7.97	$ 4.77	$ 4.33	$ 3.50	$ 2.71	$ 0.79	$ 27.69	$ 11.33	$ (11.99)		$ 27.69							$ 27.38	$ (0.31)
Income from discontinued operations (in dollars per unit)						$ (0.02)	$ 58.84	$ 0.52		$ 59.34	$ 1.67
Net Income per Unit (in dollars per unit)	$ 9.07	$ 5.90	$ 7.97	$ 4.77	$ 4.33	$ 3.48	$ 61.55	$ 1.31	$ 27.69	$ 70.67	$ (10.32)		$ 27.69							$ 27.38	$ (0.30)
Weighted Average Number of Units Outstanding (in units)									131,230	131,484	131,696		131,230							131,230	131,230