INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Balance Sheet) (Details)	Jun. 30, 2021 USD ($) property	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($) property	Dec. 31, 2019 USD ($)	May 31, 2018 USD ($)	Oct. 28, 2009 USD ($) item	Mar. 07, 2005 item	Mar. 02, 2005 USD ($) item	Sep. 30, 2004 USD ($) item	Aug. 31, 2004 USD ($) item	Nov. 30, 2001 USD ($) item
ASSETS
Rental Properties	$ 258,204,893	$ 264,609,887
Cash and Cash Equivalents	23,367,379	18,646,972
Rents Receivable	1,150,860	1,412,074
Real Estate Tax Escrows	566,228	534,941
Prepaid Expenses and Other Assets	5,501,597	5,054,959
Total Assets	290,207,915	291,669,602
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	282,438,864	283,444,533
Accounts Payable and Accrued Expenses	4,312,362	3,888,237
Advance Rental Payments and Security Deposits	7,659,718	7,466,134
Total Liabilities	333,738,970	333,138,647
Partners' Capital	(43,531,055)	(41,469,045)	$ (37,722,018)	$ (37,823,787)
Total Liabilities and Partners' Capital	290,207,915	291,669,602
Investment in Unconsolidated Joint Ventures	1,416,958	1,410,769
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (22,328,026)	$ (21,339,743)
NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%		50.00%
NERA 40%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	40.00%		40.00%
Investment Properties
ASSETS
Rental Properties	$ 113,368,920		$ 118,163,679
Cash and Cash Equivalents	4,876,022		4,483,939
Rents Receivable	694,582		735,902
Real Estate Tax Escrows	263,227		181,308
Prepaid Expenses and Other Assets	2,071,361		2,565,663
Total Assets	121,274,112		126,130,491
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	166,256,898		166,357,134
Accounts Payable and Accrued Expenses	1,302,656		1,360,581
Advance Rental Payments and Security Deposits	4,253,498		3,878,866
Total Liabilities	171,813,052		171,596,581
Partners' Capital	(50,538,940)		(45,466,090)
Total Liabilities and Partners' Capital	121,274,112		126,130,491
Investment in Unconsolidated Joint Ventures	1,416,958		1,453,895
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	(22,328,026)		(20,129,903)
Total Investment in Unconsolidated Joint Ventures (Net)	$ (20,911,068)		$ (18,676,009)
Total units/ condominiums
Total | property	865		865
Units to be retained | property	690		690
Units to be sold | property	175		175
Total number of units sold | property	175		175
Investment Properties | Residential buildings
Total units/ condominiums
Total | property	862		862
Investment Properties | Commercial
Total units/ condominiums
Total | property	3		3
Hamilton Essex 81
ASSETS
Rental Properties	$ 6,476,479		$ 6,866,502
Cash and Cash Equivalents	22,648		368,053
Rents Receivable	81,081		343,831
Real Estate Tax Escrows	77,015		62,383
Prepaid Expenses and Other Assets	296,522		308,350
Total Assets	6,953,745		7,949,119
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	9,941,396		9,927,607
Accounts Payable and Accrued Expenses	95,536		72,016
Advance Rental Payments and Security Deposits	161,990		300,200
Total Liabilities	10,198,922		10,299,823
Partners' Capital	(3,245,177)		(2,350,704)
Total Liabilities and Partners' Capital	6,953,745		$ 7,949,119
Partners' Capital % - NERA			50.00%
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (1,622,589)		$ (1,175,352)
Total units/ condominiums
Total	49		49				48
Units to be retained | property	49		49
Hamilton Essex 81 | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
Hamilton Essex 81 | Residential buildings
Total units/ condominiums
Total | property	48		48
Hamilton Essex 81 | Commercial
Total units/ condominiums
Total | property	1		1
Hamilton Essex Development
ASSETS
Rental Properties	$ 2,589,414		$ 2,591,904
Cash and Cash Equivalents	20,622		85,827
Rents Receivable	57,240		43,854
Prepaid Expenses and Other Assets	72,420		89,788
Total Assets	2,739,696		2,811,373
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	1,500		1,599
Total Liabilities	1,500		1,599
Partners' Capital	2,738,196		2,809,774
Total Liabilities and Partners' Capital	2,739,696		$ 2,811,373
Partners' Capital % - NERA			50.00%
Investment in Unconsolidated Joint Ventures	$ 1,369,098		$ 1,404,887
Total units/ condominiums
Total | property	1		1
Units to be retained | property	1		1
Hamilton Essex Development | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
Hamilton Essex Development | Commercial
Total units/ condominiums
Total | property	1		1
345 Franklin
ASSETS
Rental Properties	$ 5,224,951		$ 5,513,615
Cash and Cash Equivalents	203,017		243,868
Rents Receivable	31,630		6,827
Real Estate Tax Escrows	23,088		21,487
Prepaid Expenses and Other Assets	99,238		99,498
Total Assets	5,581,924		5,885,295
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	8,996,847		9,199,730
Accounts Payable and Accrued Expenses	103,668		89,688
Advance Rental Payments and Security Deposits	234,348		308,520
Total Liabilities	9,334,863		9,597,938
Partners' Capital	(3,752,939)		(3,712,643)
Total Liabilities and Partners' Capital	5,581,924		$ 5,885,295
Partners' Capital % - NERA			50.00%								50.00%
Investment in Unconsolidated Joint Ventures											$ 1,533,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (1,876,470)		$ (1,856,321)
Total units/ condominiums
Total	40		40								40
Units to be retained | property	40		40
345 Franklin | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
345 Franklin | Residential buildings
Total units/ condominiums
Total | property	40		40
Hamilton 1025
ASSETS
Rental Properties	$ 83,187		$ 86,451
Cash and Cash Equivalents	9,049		20,661
Rents Receivable	4,627
Prepaid Expenses and Other Assets	342		2,341
Total Assets	97,205		109,453
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	1,485		11,438
Total Liabilities	1,485		11,438
Partners' Capital	95,720		98,015
Total Liabilities and Partners' Capital	97,205		$ 109,453
Partners' Capital % - NERA			50.00%					50.00%
Investment in Unconsolidated Joint Ventures	$ 47,860		$ 49,008					$ 2,352,000
Total units/ condominiums
Total	176		176					176
Units to be retained	1		1					(49)
Units to be sold | property	175		175
Total number of units sold | property	175		175
Hamilton 1025 | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
Hamilton 1025 | Residential buildings
Total units/ condominiums
Total | property	175		175
Hamilton 1025 | Commercial
Total units/ condominiums
Total | property	1		1
Hamilton Minuteman
ASSETS
Rental Properties	$ 4,847,230		$ 5,160,011
Cash and Cash Equivalents	132,985		162,471
Rents Receivable	5,580		1,407
Real Estate Tax Escrows	41,918		25,341
Prepaid Expenses and Other Assets	19,670		33,062
Total Assets	5,047,383		5,382,292
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	5,916,460		5,908,276
Accounts Payable and Accrued Expenses	49,723		64,549
Advance Rental Payments and Security Deposits	140,039		147,506
Total Liabilities	6,106,222		6,120,331
Partners' Capital	(1,058,839)		(738,039)
Total Liabilities and Partners' Capital	5,047,383		$ 5,382,292
Partners' Capital % - NERA			50.00%						50.00%
Investment in Unconsolidated Joint Ventures									$ 5,075,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (529,420)		$ (369,020)
Total units/ condominiums
Total	42		42						42
Units to be retained | property	42		42
Hamilton Minuteman | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
Hamilton Minuteman | Residential buildings
Total units/ condominiums
Total | property	42		42
Hamilton on Main Apts
ASSETS
Rental Properties	$ 14,739,183		$ 15,570,896
Cash and Cash Equivalents	640,754		553,842
Rents Receivable	63,123		56,713
Real Estate Tax Escrows	121,206		72,097
Prepaid Expenses and Other Assets	186,140		175,465
Total Assets	15,750,406		16,429,013
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	16,849,171		16,833,120
Accounts Payable and Accrued Expenses	207,351		157,567
Advance Rental Payments and Security Deposits	425,766		440,458
Total Liabilities	17,482,288		17,431,145
Partners' Capital	(1,731,882)		(1,002,132)
Total Liabilities and Partners' Capital	15,750,406		$ 16,429,013
Partners' Capital % - NERA			50.00%							50.00%
Investment in Unconsolidated Joint Ventures										$ 8,000,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (865,941)		$ (501,066)
Total units/ condominiums
Total	148		148							280
Units to be retained | property	148		148
Hamilton on Main Apts | NERA 50%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	50.00%
Hamilton on Main Apts | Residential buildings
Total units/ condominiums
Total | property	148		148
Dexter Park
ASSETS
Rental Properties	$ 79,408,476		$ 82,374,300
Cash and Cash Equivalents	3,846,947		3,049,217
Rents Receivable	451,301		283,270
Prepaid Expenses and Other Assets	1,397,029		1,857,159
Total Assets	85,103,753		87,563,946
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	124,553,024		124,488,401		$ 82,000,000
Accounts Payable and Accrued Expenses	843,393		963,724
Advance Rental Payments and Security Deposits	3,291,355		2,682,182
Total Liabilities	128,687,772		128,134,307
Partners' Capital	(43,584,019)		(40,570,361)
Total Liabilities and Partners' Capital	85,103,753		$ 87,563,946
Partners' Capital % - NERA			40.00%			40.00%
Investment in Unconsolidated Joint Ventures						$ 15,925,000
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (17,433,608)		$ (16,228,145)
Total units/ condominiums
Total	409		409			409
Units to be retained | property	409		409
Dexter Park | NERA 40%
LIABILITIES AND PARTNERS' CAPITAL
Partners' Capital % - NERA	40.00%
Dexter Park | Residential buildings
Total units/ condominiums
Total | property	409		409