Name:	nen_DebtInstrumentCovenantConsolidatedInterestCoverageRatio
Namespace Prefix:	nen_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Represents the ratio of consolidated total debt to consolidated adjusted earnings before, interest, taxes, depreciation and amortization allowed under the terms of the senior credit facilities' covenants.

No definition available.

Name:	nen_DebtInstrumentCovenantConsolidatedLeverageRatio
Namespace Prefix:	nen_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Represents the debt ratio allowed under the terms of the senior credit facilities' covenants.

No definition available.

Name:	nen_DebtInstrumentCovenantDebtYieldPercentage
Namespace Prefix:	nen_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Maximum times the trailing 12 months EBITDA can be used, as per the debt instrument covenants.

No definition available.

Name:	nen_DebtInstrumentCovenantMaximumEbitdaUsageRatio
Namespace Prefix:	nen_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

The maximum amount of liquidity as per the debt instrument covenants.

No definition available.

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

Represents the pledged interest ownership percentage.

No definition available.

Name:	nen_PledgedInterestOwnershipPercentage
Namespace Prefix:	nen_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The amount of deposits which the partnership is required to maintain with the lender in order for commitment fee to be waived during such period.

No definition available.

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

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Indicates type of variable interest rate on debt instrument.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

Name:	us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

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

Amount of the fee for available but unused credit capacity under the credit facility.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Name:	us-gaap_LineOfCreditFacilityCommitmentFeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

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

No definition available.