INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Balance Sheet) (Details)	Dec. 31, 2020 USD ($) item	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($) item	May 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 28, 2009 USD ($) item	Oct. 03, 2005 USD ($) item	Mar. 02, 2005 USD ($) item	Sep. 30, 2004 USD ($) item	Aug. 31, 2004 USD ($) item	Nov. 30, 2001 USD ($) item
ASSETS
Rental Properties	$ 264,609,887	$ 278,363,988
Cash and Cash Equivalents	18,646,972	7,546,324
Rents Receivable	1,412,074	484,610
Real Estate Tax Escrows	534,941	446,781
Prepaid Expenses and Other Assets	5,054,959	6,021,544
Total Assets	291,669,602	294,293,649
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	283,444,533	281,771,246
Accounts Payable and Accrued Expenses	3,888,237	4,274,267
Advance Rental Payments and Security Deposits	7,466,134	8,101,835
Total Liabilities	333,138,647	332,117,437
Partners' Capital	(41,469,045)	(37,823,788)	$ (35,624,010)		$ (35,315,177)
Total Liabilities and Partners' Capital	291,669,602	294,293,649
Investment in Unconsolidated Joint Ventures	1,410,769	1,430,402
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (21,339,743)	$ (19,970,089)
NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%	50.00%	50.00%
NERA 40%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	40.00%	40.00%	40.00%
Investment Properties
ASSETS
Rental Properties	$ 115,699,932	$ 120,639,006	$ 125,170,859
Assets held for sale			645,137
Cash and Cash Equivalents	3,582,550	3,241,512	2,960,323
Rents Receivable	653,051	305,729	534,504
Real Estate Tax Escrows	233,125	201,102	219,004
Prepaid Expenses and Other Assets	2,094,682	2,242,597	1,710,791
Total Assets	122,263,340	126,629,946	131,240,618
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	166,308,029	166,404,256	166,492,692
Accounts Payable and Accrued Expenses	1,045,804	1,300,598	1,396,458
Advance Rental Payments and Security Deposits	3,214,958	4,054,640	3,592,174
Total Liabilities	170,568,791	171,759,494	171,481,324
Partners' Capital	(48,305,451)	(45,129,548)	(40,240,706)
Total Liabilities and Partners' Capital	122,263,340	126,629,946	131,240,618
Investment in Unconsolidated Joint Ventures	1,410,769	1,430,402	1,985,680
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	(21,339,743)	(19,970,089)	(18,351,562)
Total Investment in Unconsolidated Joint Ventures (Net)	$ (19,928,974)	$ (18,539,687)	$ (16,365,882)
Total units/ condominiums
Total | item	865	913	913
Units to be retained | item	690	690	690
Units to be sold | item			224
Total number of units sold | item	175	175	221
Unsold units | item			3
Units unsold with deposits for future sale | item			1
Investment Properties | Residential buildings
Total units/ condominiums
Total | item	862	910	910
Investment Properties | Commercial
Total units/ condominiums
Total | item	3	3	3
Hamilton Essex 81
ASSETS
Rental Properties	$ 6,649,177	$ 7,083,307	$ 7,222,446
Cash and Cash Equivalents	252,878	197,467	131,634
Rents Receivable	28,181	217,779	199,425
Real Estate Tax Escrows	71,203	66,410	71,579
Prepaid Expenses and Other Assets	281,503	303,876	267,028
Total Assets	7,282,942	7,868,839	7,892,112
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	9,934,502	9,920,713	9,906,924
Accounts Payable and Accrued Expenses	68,741	81,718	196,896
Advance Rental Payments and Security Deposits	208,851	321,205	259,821
Total Liabilities	10,212,094	10,323,636	10,363,641
Partners' Capital	(2,929,152)	(2,454,797)	(2,471,529)
Total Liabilities and Partners' Capital	$ 7,282,942	$ 7,868,839	$ 7,892,112
Partners' Capital % - NERA	50.00%	50.00%	50.00%
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (1,464,576)	$ (1,227,399)	$ (1,235,765)
Total units/ condominiums
Total | item	49	49	49
Units to be retained | item	49	49	49
Hamilton Essex 81 | Residential buildings
Total units/ condominiums
Total | item	48	48	48
Hamilton Essex 81 | Commercial
Total units/ condominiums
Total | item	1	1	1
Hamilton Essex Development
ASSETS
Rental Properties	$ 2,590,659	$ 2,593,148	$ 2,595,638
Cash and Cash Equivalents	55,322	49,460	118,093
Rents Receivable		33,072	28,329
Prepaid Expenses and Other Assets	80,008	97,716	115,491
Total Assets	2,725,989	2,773,396	2,857,551
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	3,200	2,600	1,750
Total Liabilities	3,200	2,600	1,750
Partners' Capital	2,722,789	2,770,796	2,855,801
Total Liabilities and Partners' Capital	$ 2,725,989	$ 2,773,396	$ 2,857,551
Partners' Capital % - NERA	50.00%	50.00%	50.00%
Investment in Unconsolidated Joint Ventures	$ 1,361,394	$ 1,385,398	$ 1,427,901
Total units/ condominiums
Total | item	1	1	1
Units to be retained | item	1	1	1
Hamilton Essex Development | Commercial
Total units/ condominiums
Total | item	1	1	1
345 Franklin
ASSETS
Rental Properties	$ 5,373,751	$ 5,678,703	$ 6,005,953
Cash and Cash Equivalents	156,073	223,691	94,349
Rents Receivable	37,127		6,872
Real Estate Tax Escrows	19,874	19,985	19,863
Prepaid Expenses and Other Assets	89,636	84,228	64,930
Total Assets	5,676,461	6,006,607	6,191,967
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	9,099,301	9,298,174	9,489,257
Accounts Payable and Accrued Expenses	87,731	77,908	51,932
Advance Rental Payments and Security Deposits	227,908	325,682	249,546
Total Liabilities	9,414,940	9,701,764	9,790,735
Partners' Capital	(3,738,479)	(3,695,157)	(3,598,768)
Total Liabilities and Partners' Capital	$ 5,676,461	$ 6,006,607	$ 6,191,967
Partners' Capital % - NERA	50.00%	50.00%	50.00%								50.00%
Investment in Unconsolidated Joint Ventures											$ 1,533,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (1,869,240)	$ (1,847,579)	$ (1,799,384)
Total units/ condominiums
Total | item	40	40	40								40
Units to be retained | item	40	40	40
345 Franklin | Residential buildings
Total units/ condominiums
Total | item	40	40	40
Hamilton 1025
ASSETS
Rental Properties	$ 84,819	$ 88,083
Assets held for sale			$ 265,622
Cash and Cash Equivalents	13,443	8,186	125,611
Rents Receivable	3,005		2,977
Prepaid Expenses and Other Assets	407	1,567	22,439
Total Assets	101,674	97,836	416,649
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	2,924	7,828	33,282
Advance Rental Payments and Security Deposits			7,187
Total Liabilities	2,924	7,828	40,469
Partners' Capital	98,750	90,008	376,180
Total Liabilities and Partners' Capital	$ 101,674	$ 97,836	$ 416,649
Partners' Capital % - NERA	50.00%	50.00%	50.00%					50.00%
Investment in Unconsolidated Joint Ventures	$ 49,375	$ 45,004	$ 188,090					$ 2,352,000
Total units/ condominiums
Total | item	176	176	176					176
Units to be retained | item	1	1	1					(49)
Units to be sold | item			177
Total number of units sold | item	175	175	174
Unsold units | item			2
Units unsold with deposits for future sale | item			1
Hamilton 1025 | Residential buildings
Total units/ condominiums
Total | item	175	175	175
Hamilton 1025 | Commercial
Total units/ condominiums
Total | item	1	1	1
Hamilton Bay Apts
ASSETS
Assets held for sale			$ 379,515
Cash and Cash Equivalents			258,487
Prepaid Expenses and Other Assets			113,164
Total Assets			751,166
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses			9,498
Advance Rental Payments and Security Deposits			2,291
Total Liabilities			11,789
Partners' Capital			739,377
Total Liabilities and Partners' Capital			$ 751,166
Partners' Capital % - NERA			50.00%				50.00%
Investment in Unconsolidated Joint Ventures			$ 369,689				$ 2,500,000
Total units/ condominiums
Total | item			48				168
Units to be retained | item							(48)
Units to be sold | item			48
Total number of units sold | item			47
Unsold units | item			1
Hamilton Bay Apts | Residential buildings
Total units/ condominiums
Total | item			48
Hamilton Minuteman
ASSETS
Rental Properties	$ 4,998,436	$ 5,323,570	$ 5,639,497
Cash and Cash Equivalents	159,599	95,965	99,701
Rents Receivable	3,816	221	3,711
Real Estate Tax Escrows	35,849	29,110	30,801
Prepaid Expenses and Other Assets	23,198	23,831	19,476
Total Assets	5,220,898	5,472,697	5,793,186
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	5,912,368	5,904,185	5,896,001
Accounts Payable and Accrued Expenses	50,514	47,740	48,866
Advance Rental Payments and Security Deposits	137,792	151,180	124,684
Total Liabilities	6,100,674	6,103,105	6,069,551
Partners' Capital	(879,776)	(630,408)	(276,365)
Total Liabilities and Partners' Capital	$ 5,220,898	$ 5,472,697	$ 5,793,186
Partners' Capital % - NERA	50.00%	50.00%	50.00%						50.00%
Investment in Unconsolidated Joint Ventures									$ 5,075,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (439,888)	$ (315,204)	$ (138,183)
Total units/ condominiums
Total | item	42	42	42						42
Units to be retained | item	42	42	42
Hamilton Minuteman | Residential buildings
Total units/ condominiums
Total | item	42	42	42
Hamilton on Main Apts
ASSETS
Rental Properties	$ 15,239,672	$ 15,891,917	$ 16,718,616
Cash and Cash Equivalents	520,150	480,899	160,310
Rents Receivable	65,511	11,284	23,845
Real Estate Tax Escrows	106,199	85,597	96,761
Prepaid Expenses and Other Assets	148,796	158,714	64,371
Total Assets	16,080,328	16,628,411	17,063,903
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	16,841,145	16,825,094	16,809,043
Accounts Payable and Accrued Expenses	156,923	282,855	186,461
Advance Rental Payments and Security Deposits	424,314	479,585	389,084
Total Liabilities	17,422,382	17,587,534	17,384,588
Partners' Capital	(1,342,054)	(959,123)	(320,685)
Total Liabilities and Partners' Capital	$ 16,080,328	$ 16,628,411	$ 17,063,903
Partners' Capital % - NERA	50.00%	50.00%	50.00%							50.00%
Investment in Unconsolidated Joint Ventures										$ 8,000,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (671,027)	$ (479,562)	$ (160,343)
Total units/ condominiums
Total | item	148	148	148							280
Units to be retained | item	148	148	148
Hamilton on Main Apts | Residential buildings
Total units/ condominiums
Total | item	148	148	148
Dexter Park
ASSETS
Rental Properties	$ 80,763,418	$ 83,980,278	$ 86,988,709
Cash and Cash Equivalents	2,425,085	2,185,844	1,972,138
Rents Receivable	515,411	43,373	269,345
Prepaid Expenses and Other Assets	1,471,134	1,572,665	1,043,892
Total Assets	85,175,048	87,782,160	90,274,084
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	124,520,713	124,456,090	124,391,467	$ 82,000,000
Accounts Payable and Accrued Expenses	675,771	799,949	867,773
Advance Rental Payments and Security Deposits	2,216,093	2,776,988	2,559,561
Total Liabilities	127,412,577	128,033,027	127,818,801
Partners' Capital	(42,237,529)	(40,250,867)	(37,544,717)
Total Liabilities and Partners' Capital	$ 85,175,048	$ 87,782,160	$ 90,274,084
Partners' Capital % - NERA	40.00%	40.00%	40.00%			40.00%
Investment in Unconsolidated Joint Ventures						$ 15,925,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (16,895,013)	$ (16,100,347)	$ (15,017,887)
Total units/ condominiums
Total | item	409	409	409
Units to be retained | item	409	409	409
Dexter Park | Residential buildings
Total units/ condominiums
Total | item	409	409	409			409