Name:	dei_EntityListingDepositoryReceiptRatio
Namespace Prefix:	dei_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

Represents the ratio of depositary receipts to Class A units.

No definition available.

Name:	nen_DepositaryReceiptExchangeRatioForClassUnits
Namespace Prefix:	nen_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the forward split of depositary receipts listed on the NYSE Amex as authorized by the entity.

No definition available.

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

- References

No definition available.

Name:	nen_EarningsPerDepositoryReceiptAbstract
Namespace Prefix:	nen_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the net income (loss) allocated to each outstanding depository receipt.

No definition available.

Name:	nen_NetIncomeLossPerOutstandingDepositoryReceipt
Namespace Prefix:	nen_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	duration

Represents the distributions per depository receipt.

No definition available.

Name:	nen_PartnersCapitalAccountDistributionPerDepositoryReceipt
Namespace Prefix:	nen_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	instant

Represents the fixed distribution percentages of the holders of units based on which the entity is required to purchase the proportionate number of specific units with every purchase of depository receipts.

No definition available.

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

Represents the number of classes of limited partners.

No definition available.

Name:	nen_PartnersCapitalAccountNumberOfClassesOfPartners
Namespace Prefix:	nen_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the quarterly distributions per depository receipt.

No definition available.

Name:	nen_PartnersCapitalAccountQuarterlyDistributionPerDepositoryReceipt
Namespace Prefix:	nen_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

Represents the amount of quarterly distribution per unit of limited partner interest.

No definition available.

Name:	nen_PartnersCapitalAccountQuarterlyDistributionPerUnitOfLimitedPartnerInterest
Namespace Prefix:	nen_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

The amount of total distributions per depository receipt.

No definition available.

Name:	nen_PartnersCapitalAccountTotalDistributionPerDepositoryReceipt
Namespace Prefix:	nen_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

The amount of total distribution per unit of limited partner interest.

No definition available.

Name:	nen_PartnersCapitalAccountTotalDistributionPerUnitOfLimitedPartnerInterest
Namespace Prefix:	nen_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

The value of distributions in a period.

No definition available.

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

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.

No definition available.

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

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_LimitedPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_GeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=nen_LimitedClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: