RENTAL PROPERTIES - Acquisition (Details)		6 Months Ended
Jun. 18, 2025 USD ($) item	Jun. 30, 2025 USD ($)
RENTAL PROPERTIES
Purchase of rental property		$ 108,885,341
Belmont Massachusetts property
RENTAL PROPERTIES
Borrowings used for purchase of property	$ 40,000,000
Loan for purchase of property	67,500,000
Mixed use property
RENTAL PROPERTIES
Purchase price of real estate properties	172,000,000
Closing costs	$ 218,000
Mixed use property \| Residential
RENTAL PROPERTIES
Number of real estate property purchased \| item	396
Mixed use property \| Commercial
RENTAL PROPERTIES
Number of real estate property purchased \| item	3
Commercial property
RENTAL PROPERTIES
Purchase price of real estate properties	$ 3,000,000
Commercial property \| Commercial
RENTAL PROPERTIES
Number of real estate property purchased \| item	2
Properties at brighton and concord avenue \| Commercial
RENTAL PROPERTIES
Purchase price allocated to the value of the in-place leases	$ 4,714,000
Purchase price allocated to the value of the tenant relationships	305,000
Purchase price allocated to the value of below market leases	$ 1,165,000
Amortization period of value of the in-place leases	12 months
Amortization period of value of the tenant relationships	36 months

Represents the closing costs associated with the transaction.

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

The number of real estate property purchased.

+ References

No definition available.

+ Details

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- Definition

Represents the amortization period of value of the in-place leases.

+ References

No definition available.

+ Details

Name:	nen_RealEstatePropertyLeaseAmortizationTerm
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

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

- Definition

Represents the aggregate purchase price of real estate properties acquired by the entity allocated to below-market leases.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Represents the aggregate purchase price of real estate properties acquired by the entity allocated to tenant relationships.

+ References

No definition available.

+ Details

Name:	nen_RealEstatePropertyPurchasePriceAllocationTenantRelationships
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of real estate property purchase price payment financed through borrowings under master credit facility.

+ References

No definition available.

+ Details

Name:	nen_RealEstatePropertyPurchasePricePaymentFinancedThroughBorrowingsUnderMasterCreditFacility
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of real estate property purchase price payment financed through interim loan.

+ References

No definition available.

+ Details

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

- Definition

Represents the amortization period of value of the tenant relationships.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow from the acquisition of property as primarily intended to generate income for its owner.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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