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Represents the period for which the entity is required to make interest only payments on the debt instrument.

No definition available.

Name:	nen_DebtInstrumentTermForWhichInterestOnlyPaymentsRequired
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Represents the number of units retained for long-term investment.

No definition available.

Name:	nen_NumberOfUnitsInRealEstatePropertyRetainedForLongTermInvestment
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Data Type:	xbrli:integerItemType
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Represents the number of units sold.

No definition available.

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The number of units under a purchase and sale agreement.

No definition available.

Name:	nen_NumberOfUnitsInRealEstatePropertyUnderPurchaseAndSaleAgreement
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Represents the number of units unsold by the entity.

No definition available.

Name:	nen_NumberOfUnitsInRealEstatePropertyUnsold
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Period Type:	instant

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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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
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Data Type:	xbrli:durationItemType
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This element represents the aggregate cost of investments accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
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-Section S99
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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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

No definition available.

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total contributions made by each class of partners (i.e., general, limited and preferred partners).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

No definition available.

Name:	us-gaap_ProceedsFromIssuanceOfDebt
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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.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Name:	us-gaap_SecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nen_Hamilton1025LLCMember
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