Represents that additional interest rate margin on a debt instrument.

No definition available.

Name:	nen_AdditionalApplicableMarginRate
Namespace Prefix:	nen_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the ratio of consolidated adjusted earnings before interest, taxes, depreciation and amortization to interest expense, which is necessary to be maintained under the terms of the senior credit facilities' covenants.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	nen_DebtInstrumentCovenantConsolidatedLeverageRatio
Namespace Prefix:	nen_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	nen_DebtInstrumentCovenantDebtYiledPercentage
Namespace Prefix:	nen_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Length of extension of credit line, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Maximum borrowing capacity during the modifications period 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.

+ References

No definition available.

+ Details

Name:	nen_LineOfCreditFacilityMaximumBorrowingCapacityDuringModificationPeriod
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the level of tangible net worth required to maintain.

+ References

No definition available.

+ Details

Name:	nen_TangibleNetWorth
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=nen_Nen_FederalFundsRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=nen_CurrentCovenantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=nen_RevisedCovenantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=nen_AdditionalRevisedCovenantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SUBSEQUENT EVENTS (Details)				6 Months Ended
SUBSEQUENT EVENTS (Details)	Jul. 30, 2021 USD ($)	Jul. 29, 2021	Jul. 31, 2014 USD ($)	Jun. 30, 2021 USD ($)	Aug. 31, 2017 USD ($)
Minimum
Subsequent events
Debt service coverage ratio				1.6
Tangible Net Worth				$ 150,000,000
Maximum
Subsequent events
Leverage ratio				65.00%
Line of Credit
Subsequent events
Term of debt			3 years
Maximum borrowings			$ 25,000,000
Amount of refinancing costs					$ 128,000
Line of Credit \| Subsequent event
Subsequent events
Term of debt	3 years
Line of credit extension term	12 months
Maximum borrowings	$ 25,000,000
Maximum borrowings during modification period	17,000,000
Amount of refinancing costs	$ 125,000
Line of Credit \| Federal Funds Rate
Subsequent events
Variable interest rate spread			0.50%
Line of Credit \| LIBOR
Subsequent events
Additional applicable margin rate			2.50%
Variable interest rate spread			1.00%
Line of Credit \| LIBOR \| Subsequent event
Subsequent events
Variable interest rate spread	300.00%	350.00%
Current covenants \| Line of Credit \| Subsequent event
Subsequent events
Debt service coverage ratio	1.60
Tangible Net Worth	$ 200,000,000
Leverage ratio	65.00%
Debt yield	9.50%
Revised covenants inplace until September 30, 2022 \| Line of Credit \| Subsequent event
Subsequent events
Debt service coverage ratio	1.35
Tangible Net Worth	$ 175,000,000
Leverage ratio	70.00%
Debt yield	8.50%
Revised Covenants in place until December 31, 2022 \| Line of Credit \| Subsequent event
Subsequent events
Debt yield	9.00%