INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Details 2) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Hamilton Essex 81 item	Dec. 31, 2011 Hamilton Essex 81 item	Dec. 31, 2010 Hamilton Essex 81 item	Dec. 31, 2012 Hamilton Essex 81 NERA 50%	Dec. 31, 2011 Hamilton Essex 81 NERA 50%	Dec. 31, 2010 Hamilton Essex 81 NERA 50%	Dec. 31, 2012 Hamilton Essex 81 Apartments item	Dec. 31, 2011 Hamilton Essex 81 Apartments item	Dec. 31, 2010 Hamilton Essex 81 Apartments item	Dec. 31, 2012 Hamilton Essex 81 Commercial item	Dec. 31, 2011 Hamilton Essex 81 Commercial item	Dec. 31, 2010 Hamilton Essex 81 Commercial item	Dec. 31, 2012 Hamilton Essex Development item	Dec. 31, 2011 Hamilton Essex Development item	Dec. 31, 2010 Hamilton Essex Development item	Dec. 31, 2012 Hamilton Essex Development NERA 50%	Dec. 31, 2011 Hamilton Essex Development NERA 50%	Dec. 31, 2010 Hamilton Essex Development NERA 50%	Dec. 31, 2012 Hamilton Essex Development Commercial item	Dec. 31, 2011 Hamilton Essex Development Commercial item	Dec. 31, 2010 Hamilton Essex Development Commercial item	Dec. 31, 2012 345 Franklin item	Dec. 31, 2011 345 Franklin item	Dec. 31, 2010 345 Franklin item	Nov. 30, 2001 345 Franklin item	Dec. 31, 2012 345 Franklin NERA 50%	Dec. 31, 2011 345 Franklin NERA 50%	Dec. 31, 2010 345 Franklin NERA 50%	Dec. 31, 2012 345 Franklin Apartments item	Dec. 31, 2011 345 Franklin Apartments item	Dec. 31, 2010 345 Franklin Apartments item	Dec. 31, 2012 Hamilton 1025 item	Dec. 31, 2011 Hamilton 1025 item	Dec. 31, 2010 Hamilton 1025 item	Mar. 02, 2005 Hamilton 1025 item	Dec. 31, 2012 Hamilton 1025 NERA 50%	Dec. 31, 2011 Hamilton 1025 NERA 50%	Dec. 31, 2010 Hamilton 1025 NERA 50%	Dec. 31, 2012 Hamilton 1025 Apartments item	Dec. 31, 2011 Hamilton 1025 Apartments item	Dec. 31, 2010 Hamilton 1025 Apartments item	Dec. 31, 2012 Hamilton 1025 Commercial item	Dec. 31, 2011 Hamilton 1025 Commercial item	Dec. 31, 2010 Hamilton 1025 Commercial item	Feb. 03, 2013 Hamilton Bay Sales item	Dec. 31, 2012 Hamilton Bay Sales item	Dec. 31, 2011 Hamilton Bay Sales item	Dec. 31, 2010 Hamilton Bay Sales item	Apr. 30, 2008 Hamilton Bay Sales item	Oct. 03, 2005 Hamilton Bay Sales item	Dec. 31, 2012 Hamilton Bay Sales NERA 50%	Dec. 31, 2011 Hamilton Bay Sales NERA 50%	Dec. 31, 2010 Hamilton Bay Sales NERA 50%	Dec. 31, 2012 Hamilton Bay Sales Apartments item	Dec. 31, 2011 Hamilton Bay Sales Apartments item	Dec. 31, 2010 Hamilton Bay Sales Apartments item	Dec. 31, 2012 Hamilton Bay item	Dec. 31, 2011 Hamilton Bay item	Dec. 31, 2010 Hamilton Bay item	Oct. 03, 2005 Hamilton Bay item	Dec. 31, 2012 Hamilton Bay NERA 50%	Dec. 31, 2011 Hamilton Bay NERA 50%	Dec. 31, 2010 Hamilton Bay NERA 50%	Dec. 31, 2012 Hamilton Bay Apartments item	Dec. 31, 2011 Hamilton Bay Apartments item	Dec. 31, 2010 Hamilton Bay Apartments item	Dec. 31, 2012 Hamilton Minuteman item	Dec. 31, 2011 Hamilton Minuteman item	Dec. 31, 2010 Hamilton Minuteman item	Sep. 30, 2004 Hamilton Minuteman item	Dec. 31, 2012 Hamilton Minuteman NERA 50%	Dec. 31, 2011 Hamilton Minuteman NERA 50%	Dec. 31, 2010 Hamilton Minuteman NERA 50%	Dec. 31, 2012 Hamilton Minuteman Apartments item	Dec. 31, 2011 Hamilton Minuteman Apartments item	Dec. 31, 2010 Hamilton Minuteman Apartments item	Dec. 31, 2012 Hamilton on Main item	Dec. 31, 2011 Hamilton on Main item	Dec. 31, 2010 Hamilton on Main item	May 31, 2008 Hamilton on Main item	Aug. 31, 2004 Hamilton on Main item	Dec. 31, 2012 Hamilton on Main NERA 50%	Dec. 31, 2011 Hamilton on Main NERA 50%	Dec. 31, 2010 Hamilton on Main NERA 50%	Dec. 31, 2012 Hamilton on Main Apartments item	Dec. 31, 2011 Hamilton on Main Apartments item	Dec. 31, 2010 Hamilton on Main Apartments item	Dec. 31, 2012 Dexter Park item	Dec. 31, 2011 Dexter Park item	Dec. 31, 2010 Dexter Park item	Oct. 28, 2009 Dexter Park item	Dec. 31, 2012 Dexter Park NERA 40%	Dec. 31, 2011 Dexter Park NERA 40%	Dec. 31, 2010 Dexter Park NERA 40%	Dec. 31, 2012 Dexter Park Apartments item	Dec. 31, 2011 Dexter Park Apartments item	Dec. 31, 2010 Dexter Park Apartments item	Dec. 31, 2012 Total item	Dec. 31, 2011 Total item	Dec. 31, 2010 Total item	Dec. 31, 2012 Total NERA 50%	Dec. 31, 2011 Total NERA 50%	Dec. 31, 2010 Total NERA 50%	Dec. 31, 2012 Total NERA 40%	Dec. 31, 2011 Total NERA 40%	Dec. 31, 2010 Total NERA 40%	Dec. 31, 2012 Total Apartments item	Dec. 31, 2011 Total Apartments item	Dec. 31, 2010 Total Apartments item	Dec. 31, 2012 Total Commercial item	Dec. 31, 2011 Total Commercial item	Dec. 31, 2010 Total Commercial item
ASSETS
Rental Properties	$ 95,435,850	$ 98,924,534			$ 9,103,858	$ 9,454,959	$ 9,827,917										$ 2,610,574	$ 2,613,064	$ 2,595,266							$ 7,885,745	$ 8,229,651	$ 8,648,591								$ 5,621,970	$ 5,863,176	$ 6,078,526												$ 1,844,219	$ 1,916,445	$ 2,006,989									$ 6,975,854	$ 7,257,981	$ 7,569,060								$ 7,020,471	$ 7,256,528	$ 7,582,687								$ 21,148,813	$ 21,939,796	$ 22,822,785									$ 107,496,918	$ 112,921,940	$ 118,468,247								$ 169,708,422	$ 177,453,541	$ 185,600,068
Cash & Cash Equivalents	6,981,906	4,050,157	3,245,361	2,879,663	27,848	47,526	2,833										20,214	1,529	29,596							3,533	17,027	25,617								2,706	1,848	736												20,695	19,416	48,053									62,473	5,026	57,956								44,170	31,125	51,637								103,990	90,940	19,325									941,391	836,347	754,066								1,227,018	1,050,783	989,818
Rent Receivable	475,083	434,252			44,005	73,459	24,062																			600		8,887								7,283	15,682	10,088												2,200		2,224									2,686	2,512	2,295								2,626	7,457	683								11,108	8,593	10,686									35,250	86,722	125,475								105,758	194,425	184,400
Real Estate Tax Escrow	449,652	401,325			49,793	98,610	85,348																			20,242	18,360	18,649								74,443	64,464	58,089																							41,225	89,760	82,370								43,612	43,864	34,331								70,364	104,505	98,036									424,159	582,028	484,566								723,838	1,001,592	861,390
Prepaid Expenses & Other Assets	3,073,890	3,866,652			61,895	59,508	49,518										505	493	480							75,222	54,276	50,720								33,659	88,524	76,810												127,530	167,811	209,610									14,345	95,190	94,181								48,715	54,023	43,655								154,396	180,899	418,289									1,367,274	1,216,214	1,089,897								1,883,541	1,916,937	2,033,161
Financing & Leasing Fees	1,135,936	919,187			64,116	71,108	96,105										4,325	6,987	4,175							8,164	16,330	24,496								19,645	24,672	29,698												5,505	6,570	11,634									26,243	32,605	38,966								15,950	19,918	23,887								14,581	21,442	28,304									399,678	458,995	518,395								558,206	658,626	775,660
Total Assets	121,538,490	125,376,764			9,351,515	9,805,169	10,085,783										2,635,617	2,622,073	2,629,517							7,993,505	8,335,644	8,776,960								5,759,706	6,058,364	6,253,948												2,000,148	2,110,241	2,278,510									7,122,825	7,483,074	7,844,829								7,175,545	7,412,916	7,736,879								21,503,252	22,346,175	23,397,425									110,664,670	116,102,247	121,440,647								174,206,783	182,275,903	190,444,498
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	138,055,522	139,161,612			8,352,317	8,462,041	8,566,871										2,093,184	2,144,796	2,162,000							6,850,179	7,019,119	7,176,827								4,934,741	4,995,487	5,000,000												4,702,087	4,750,000	4,750,000									1,668,000	1,668,000	1,668,000								5,433,472	5,500,000	5,500,000								15,611,045	15,887,203	16,151,526									88,611,686	89,733,192	89,914,000								138,256,711	140,159,839	140,889,224
Accounts Payable & Accrued Expense	2,361,942	2,253,696			34,673	32,238	33,190										6,319	6,309	6,239							93,810	15,323	36,027								49,566	48,236	43,541												7,481	12,682	6,346									49,690	28,690	5,693								58,378	58,596	65,588								204,413	212,224	206,997									843,422	820,603	787,584								1,347,752	1,234,900	1,191,205
Advance Rental Pmts & Security Deposits	3,636,704	3,603,708			175,871	152,940	132,044																			140,759	114,179	129,188								80,264	69,970	63,965												25,147	20,027	20,044									86,028	85,575	80,772								71,025	69,592	61,762								273,302	257,780	226,689									1,919,573	1,800,113	1,684,843								2,771,968	2,570,176	2,399,308
Total Liabilities	144,054,168	146,687,616			8,562,861	8,647,219	8,732,105										2,099,503	2,151,105	2,168,239							7,084,748	7,148,621	7,342,042								5,064,570	5,113,694	5,107,506												1,700,628	1,700,709	1,694,390									4,837,806	4,864,265	4,836,465								5,562,875	5,628,188	5,627,350								16,088,760	16,357,207	16,585,212									91,374,681	92,353,908	92,386,428								142,376,432	143,964,915	144,479,737
Partners' Capital	(22,515,677)	(21,310,851)	(26,920,566)	(21,332,823)	788,654	1,157,950	1,353,679										536,114	470,968	461,278							908,757	1,187,023	1,434,918								695,135	944,670	1,146,442												299,520	409,532	584,119									2,285,019	2,618,809	3,008,364								1,612,669	1,784,728	2,109,529								5,414,492	5,988,968	6,812,213									19,289,989	23,748,339	29,054,219								31,830,352	38,310,988	45,964,761
Total Liabilities and Partners' Capital	121,538,490	125,376,764			9,351,515	9,805,169	10,085,783										2,635,617	2,622,073	2,629,517							7,993,505	8,335,644	8,776,960								5,759,706	6,058,364	6,253,948												2,000,148	2,110,241	2,278,510									7,122,825	7,483,074	7,844,829								7,175,545	7,412,916	7,736,879								21,503,252	22,346,175	23,397,425									110,664,670	116,102,247	121,440,647								174,206,783	182,275,903	190,444,498
Share of partners capital in investments								$ 394,327	$ 578,975	$ 676,839										$ 268,057	$ 235,484	$ 230,639								$ 454,379	$ 593,512	$ 717,459								$ 347,568	$ 472,335	$ 573,221													$ 149,760	$ 204,766	$ 292,060								$ 1,142,510	$ 1,309,404	$ 1,504,182								$ 806,335	$ 892,364	$ 1,054,765									$ 2,707,246	$ 2,994,484	$ 3,406,107								$ 7,715,996	$ 9,499,335	$ 11,621,688				$ 13,986,177	$ 16,780,660	$ 20,076,959	$ 6,270,181	$ 7,281,325	$ 8,455,271	$ 7,715,996	$ 9,499,335	$ 11,621,688
Percentage of ownership interest								50.00%	50.00%	50.00%										50.00%	50.00%	50.00%							50.00%	50.00%	50.00%	50.00%							50.00%	50.00%	50.00%	50.00%												50.00%	50.00%	50.00%	50.00%								50.00%	50.00%	50.00%							50.00%	50.00%	50.00%	50.00%								50.00%	50.00%	50.00%	50.00%							40.00%	40.00%	40.00%	40.00%							50.00%	50.00%	50.00%	40.00%	40.00%	40.00%
Total units/ condominiums
Total					49	49	49				48	48	48	1	1	1	1	1	1				1	1	1	40	40	40	40				40	40	40	176	176	176	176				175	175	175	1	1	1		48	48	48	20	168				48	48	48	120	120	120					120	120	120	42	42	42	42				42	42	42	148	148	148		280				148	148	148	409	409	409	409				409	409	409	1,033	1,033	1,033							1,030	1,030	1,030	3	3	3
Units to be retained					49	49	49										1	1	1							40	40	40								49	49	49	49											48	48	48												48							42	42	42								148	148	148									409	409	409								786	786	786
Units to be sold																																				127	127	127												120	120	120																																																		247	247	247
Units sold																																				127	127	127	127										105												105	105	105																					137																		232	232	232
Unsold units																																																		15	15	15																																																		15	15	15
Unsold units with deposits for future sale																																																				0