Represents the amount of quarterly fee for asset management consulting services.

No definition available.

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

- Definition

Represents the amount aggregate cost of construction, architectural services and supervision of capital projects during the reporting period.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of limited partnerships and limited liability companies in which the entity has made investments which are accounted for using the equity method of consolidation.

+ References

No definition available.

+ Details

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

- Definition

This element represents the amount of management fee incurred for payment to a management company during the reporting period.

+ References

No definition available.

+ Details

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

- Definition

Number of employees, excluding President, having ownership interest in the investment properties.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of expense charged to entity for bookkeeping and accounting services under terms of agreement with related parties, included within administrative costs.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount charged for bookkeeping and accounting services per year as included in administrative expenses.

+ References

No definition available.

+ Details

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

- Definition

Represents the charge against earnings towards management fees associated with the services provided by related party.

+ References

No definition available.

+ Details

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

- Definition

Represents the management fees expressed as a percentage of Linewt.

+ References

No definition available.

+ Details

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

- Definition

Represents the management fee expressed as a percentage of rental revenues from properties owned.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of employees who perform accounting and bookkeeping functions.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount reimbursed to related party for transfer of employee payroll.

+ References

No definition available.

+ Details

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

- Definition

The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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

- Definition

The amount of cash paid for brokerage fees during the current period. This element is intended to represent the brokerage fees paid by and between financial industry participants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

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

- Definition

A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.2(a),(b),(c),(d))
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-Publisher FASB
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-SubTopic 225
-Section 45
-Paragraph 3
-Subparagraph (k)
-URI http://asc.fasb.org/extlink&oid=6488370&loc=d3e13550-115849

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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-Topic 850
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

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

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=nen_HaroldBrownMember
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RELATED PARTY TRANSACTIONS (Details)	3 Months Ended		15 Months Ended
RELATED PARTY TRANSACTIONS (Details)	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($)
RELATED PARTY TRANSACTIONS
Management fee as percentage of gross receipts rental revenue	4.00%
Management fee as a percentage of gross receipts rental revenue of Linewt, LLC	3.00%
Management fees of related party	$ 537,000	$ 500,000
Management fee	536,715	500,207
Repairs and maintenance	1,455,621	1,627,700
Administrative expense	$ 525,736	498,255
Number of limited partnerships and limited liability companies in which the entity has invested \| item	9
Dexter Park
RELATED PARTY TRANSACTIONS
Management fee as percentage of gross receipts rental revenue	2.00%
President of Management Company
RELATED PARTY TRANSACTIONS
Quarterly fee for asset management consulting services	$ 18,750	18,750
Harold Brown \| Minimum
RELATED PARTY TRANSACTIONS
Ownership interest (as a percent)	43.20%		43.20%
Harold Brown \| Maximum
RELATED PARTY TRANSACTIONS
Ownership interest (as a percent)	56.00%		56.00%
General Partner or Management Company [Member]
RELATED PARTY TRANSACTIONS
Repairs and maintenance	$ 50,000
Administrative expense	91,000
Commercial brokerage fees	1,000
Expenses for construction, architectural services and supervision of capital projects	40,000
Costs related to professional services	182,000	309,000
Management Company [Member]
RELATED PARTY TRANSACTIONS
Reimbursement to related party for payroll transfers	811,000	712,000
Employer contributions in 401K plan	$ 0	0
Number of accounting staff of related party providing bookkeeping and accounting functions \| item	14
Fees for accounting and bookkeeping services	$ 31,250	$ 31,250
Number of employees having ownership interest in the investment properties \| item	6
Fees for accounting and bookkeeping services per year			$ 125,000
Partially owned properties
RELATED PARTY TRANSACTIONS
Management fee as percentage of gross receipts rental revenue	4.00%
Management fee	$ 179,000
Repairs and maintenance	22,000
Administrative expense	8,000
Construction, architectural services and supervision of capital projects	294,000
Amount paid to related party	$ 503,000
Residential and mixed-use properties \| Partially owned properties \| Minimum
RELATED PARTY TRANSACTIONS
Ownership interest (as a percent)	40.00%		40.00%
Residential and mixed-use properties \| Partially owned properties \| Maximum
RELATED PARTY TRANSACTIONS
Ownership interest (as a percent)	50.00%		50.00%