INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Balance Sheet) (Details)	Mar. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($)	Mar. 31, 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	$ 261,361,758	$ 264,609,887
Cash and Cash Equivalents	20,822,344	18,646,972
Rents Receivable	1,224,948	1,412,074
Real Estate Tax Escrows	546,426	534,941
Prepaid Expenses and Other Assets	4,776,893	5,054,959
Total Assets	290,132,893	291,669,602
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	282,951,918	283,444,533
Accounts Payable and Accrued Expenses	4,075,165	3,888,237
Advance Rental Payments and Security Deposits	7,187,229	7,466,134
Total Liabilities	333,064,978	333,138,647
Partners' Capital	(42,932,085)	(41,469,045)	$ (38,014,124)	$ (37,823,787)
Total Liabilities and Partners' Capital	290,132,893	291,669,602
Investment in Unconsolidated Joint Ventures	1,400,524	1,410,769
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (21,850,666)	$ (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	$ 114,497,085		$ 119,448,740
Cash and Cash Equivalents	3,525,400		5,101,077
Rents Receivable	585,804		293,379
Real Estate Tax Escrows	281,173		220,453
Prepaid Expenses and Other Assets	2,028,812		2,246,237
Total Assets	120,918,274		127,309,886
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	166,282,719		166,380,941
Accounts Payable and Accrued Expenses	1,149,977		1,036,550
Advance Rental Payments and Security Deposits	2,961,185		3,928,292
Total Liabilities	170,393,881		171,345,783
Partners' Capital	(49,475,607)		(44,035,897)
Total Liabilities and Partners' Capital	120,918,274		127,309,886
Investment in Unconsolidated Joint Ventures	1,400,524		1,460,406
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	(21,850,666)		(19,525,528)
Total Investment in Unconsolidated Joint Ventures (Net)	$ (20,450,142)		$ (18,065,122)
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	$ 6,583,704		$ 6,977,869
Cash and Cash Equivalents	66,579		336,900
Rents Receivable	31,379		215,143
Real Estate Tax Escrows	74,083		62,924
Prepaid Expenses and Other Assets	274,840		311,711
Total Assets	7,030,585		7,904,547
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	9,937,949		9,924,160
Accounts Payable and Accrued Expenses	66,760		82,063
Advance Rental Payments and Security Deposits	102,170		294,765
Total Liabilities	10,106,879		10,300,988
Partners' Capital	(3,076,294)		(2,396,441)
Total Liabilities and Partners' Capital	7,030,585		$ 7,904,547
Partners' Capital % - NERA			50.00%
Distribution and Loss in Excess of investments in Unconsolidated Joint Venture	$ (1,538,147)		$ (1,198,220)
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	$ 2,590,036		$ 2,592,526
Cash and Cash Equivalents	40,821		105,620
Rents Receivable			38,463
Prepaid Expenses and Other Assets	75,119		92,886
Total Assets	2,705,976		2,829,495
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	4,000		3,250
Total Liabilities	4,000		3,250
Partners' Capital	2,701,976		2,826,245
Total Liabilities and Partners' Capital	2,705,976		$ 2,829,495
Partners' Capital % - NERA			50.00%
Investment in Unconsolidated Joint Ventures	$ 1,350,988		$ 1,413,123
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	$ 5,289,712		$ 5,597,090
Cash and Cash Equivalents	139,721		387,085
Rents Receivable	35,916
Real Estate Tax Escrows	54,505		52,215
Prepaid Expenses and Other Assets	85,816		76,295
Total Assets	5,605,670		6,112,685
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	9,048,329		9,249,198
Accounts Payable and Accrued Expenses	106,469		103,274
Advance Rental Payments and Security Deposits	214,146		312,134
Total Liabilities	9,368,944		9,664,606
Partners' Capital	(3,763,274)		(3,551,921)
Total Liabilities and Partners' Capital	5,605,670		$ 6,112,685
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	$ (1,881,637)		$ (1,775,961)
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	$ 84,003		$ 87,267
Cash and Cash Equivalents	6,435		11,568
Rents Receivable	11,669
Prepaid Expenses and Other Assets	191		1,682
Total Assets	102,298		100,517
LIABILITIES AND PARTNERS' CAPITAL
Accounts Payable and Accrued Expenses	3,225		5,948
Total Liabilities	3,225		5,948
Partners' Capital	99,073		94,569
Total Liabilities and Partners' Capital	102,298		$ 100,517
Partners' Capital % - NERA			50.00%					50.00%
Investment in Unconsolidated Joint Ventures	$ 49,536		$ 47,284					$ 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	$ 4,914,411		$ 5,240,627
Cash and Cash Equivalents	132,455		234,919
Rents Receivable	9,749		205
Real Estate Tax Escrows	38,883		27,345
Prepaid Expenses and Other Assets	15,187		19,098
Total Assets	5,110,685		5,522,194
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	5,914,414		5,906,230
Accounts Payable and Accrued Expenses	75,274		50,102
Advance Rental Payments and Security Deposits	136,840		137,848
Total Liabilities	6,126,528		6,094,180
Partners' Capital	(1,015,843)		(571,986)
Total Liabilities and Partners' Capital	5,110,685		$ 5,522,194
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	$ (507,922)		$ (285,993)
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	$ 14,982,149		$ 15,722,824
Cash and Cash Equivalents	574,605		514,145
Rents Receivable	49,425		12,553
Real Estate Tax Escrows	113,702		77,969
Prepaid Expenses and Other Assets	177,044		185,332
Total Assets	15,896,925		16,512,823
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	16,845,158		16,829,107
Accounts Payable and Accrued Expenses	172,092		152,433
Advance Rental Payments and Security Deposits	424,300		439,382
Total Liabilities	17,441,550		17,420,922
Partners' Capital	(1,544,625)		(908,099)
Total Liabilities and Partners' Capital	15,896,925		$ 16,512,823
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	$ (772,313)		$ (454,050)
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	$ 80,053,070		$ 83,230,537
Cash and Cash Equivalents	2,564,784		3,510,840
Rents Receivable	447,666		27,015
Prepaid Expenses and Other Assets	1,400,615		1,559,233
Total Assets	84,466,135		88,327,625
LIABILITIES AND PARTNERS' CAPITAL
Mortgage Notes Payable	124,536,869		124,472,246		$ 82,000,000
Accounts Payable and Accrued Expenses	722,157		639,480
Advance Rental Payments and Security Deposits	2,083,729		2,744,163
Total Liabilities	127,342,755		127,855,889
Partners' Capital	(42,876,620)		(39,528,264)
Total Liabilities and Partners' Capital	84,466,135		$ 88,327,625
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	$ (17,150,648)		$ (15,811,306)
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