Represents the closing costs associated with the transaction.

No definition available.

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Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the useful life of constituents of rental properties.

+ References

No definition available.

+ Details

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Namespace Prefix:	nen_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the aggregate purchase price of real estate properties acquired by the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

+ Details

Name:	us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

+ Details

Name:	us-gaap_RealEstateInvestmentPropertyAtCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

+ Details

Name:	us-gaap_RealEstateInvestmentPropertyNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_RealEstateInvestmentPropertyNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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RENTAL PROPERTIES (Details)		12 Months Ended
RENTAL PROPERTIES (Details)	Jul. 14, 2023 USD ($) item	Dec. 31, 2023 USD ($) ft² item property	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 property
Rental properties
Total fixed assets		$ 440,496,897	$ 400,703,910
Less: Accumulated depreciation		(170,691,951)	(159,627,479)
Total fixed assets, net		269,804,946	241,076,431
South End neighborhood of Boston, MA
RENTAL PROPERTIES
Number of units \| item	52
Rental properties
Purchase price of real estate properties	$ 27,500,000
Closing Costs	$ 81,000
Land, improvements and parking lots
Rental properties
Total fixed assets		$ 99,162,143	87,405,897
Land, improvements and parking lots \| Minimum
Rental properties
Useful Life		15 years
Land, improvements and parking lots \| Maximum
Rental properties
Useful Life		40 years
Buildings and improvements
Rental properties
Total fixed assets		$ 277,986,334	256,035,191
Buildings and improvements \| Minimum
Rental properties
Useful Life		15 years
Buildings and improvements \| Maximum
Rental properties
Useful Life		40 years
Kitchen cabinets
Rental properties
Total fixed assets		$ 16,137,828	14,347,212
Kitchen cabinets \| Minimum
Rental properties
Useful Life		5 years
Kitchen cabinets \| Maximum
Rental properties
Useful Life		10 years
Carpets
Rental properties
Total fixed assets		$ 13,127,838	12,047,573
Carpets \| Minimum
Rental properties
Useful Life		5 years
Carpets \| Maximum
Rental properties
Useful Life		10 years
Air conditioning
Rental properties
Total fixed assets		$ 500,000	501,697
Air conditioning \| Minimum
Rental properties
Useful Life		5 years
Air conditioning \| Maximum
Rental properties
Useful Life		10 years
Laundry equipment
Rental properties
Total fixed assets		$ 568,716	553,140
Laundry equipment \| Minimum
Rental properties
Useful Life		5 years
Laundry equipment \| Maximum
Rental properties
Useful Life		7 years
Elevators
Rental properties
Total fixed assets		$ 1,885,265	1,885,265
Elevators \| Minimum
Rental properties
Useful Life		20 years
Elevators \| Maximum
Rental properties
Useful Life		40 years
Swimming pools
Rental properties
Total fixed assets		$ 1,090,604	1,090,604
Swimming pools \| Minimum
Rental properties
Useful Life		10 years
Swimming pools \| Maximum
Rental properties
Useful Life		30 years
Equipment
Rental properties
Total fixed assets		$ 21,348,556	18,716,758
Equipment \| Minimum
Rental properties
Useful Life		5 years
Equipment \| Maximum
Rental properties
Useful Life		30 years
Motor vehicles
Rental properties
Total fixed assets		$ 232,954	171,519
Useful Life		5 years
Fences
Rental properties
Total fixed assets		$ 91,620	46,872
Fences \| Minimum
Rental properties
Useful Life		5 years
Fences \| Maximum
Rental properties
Useful Life		15 years
Furniture and fixtures
Rental properties
Total fixed assets		$ 8,365,039	$ 7,902,182
Furniture and fixtures \| Minimum
Rental properties
Useful Life		5 years
Furniture and fixtures \| Maximum
Rental properties
Useful Life		7 years
Wholly owned properties
RENTAL PROPERTIES
Number of properties \| property		31
Investment Properties
RENTAL PROPERTIES
Number of units \| property		690	865	865
NERA 40%
RENTAL PROPERTIES
Ownership interest (as a percent)		40.00%	40.00%	40.00%
NERA 50%
RENTAL PROPERTIES
Ownership interest (as a percent)		50.00%	50.00%	50.00%
Residential and mixed-use properties \| Wholly owned properties
RENTAL PROPERTIES
Number of units \| item		2,943
Number of properties \| property		27
Residential and mixed-use properties \| Partially owned properties
RENTAL PROPERTIES
Number of units \| item		688
Rental properties
Area of property (in square feet) \| ft²		12,500
Residential and mixed-use properties \| Investment Properties \| Partially owned properties
RENTAL PROPERTIES
Number of properties \| item		7
Residential and mixed-use properties \| Limited Partnerships \| Partially owned properties
RENTAL PROPERTIES
Number of properties \| item		7
Residential and mixed-use properties \| NERA 40% \| Partially owned properties \| Minimum
RENTAL PROPERTIES
Ownership interest (as a percent)		40.00%
Residential and mixed-use properties \| NERA 50% \| Partially owned properties \| Maximum
RENTAL PROPERTIES
Ownership interest (as a percent)		50.00%
Condominium \| Wholly owned properties
RENTAL PROPERTIES
Number of units \| item		19
Number of properties \| property		1
Commercial
RENTAL PROPERTIES
Number of properties \| property		2
Commercial \| Wholly owned properties
RENTAL PROPERTIES
Number of properties \| property		4
Rental properties
Area of property (in square feet) \| ft²		130,000
Commercial \| Investment Properties
RENTAL PROPERTIES
Number of units \| property		3	3	3