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

No definition available.

Name:	nen_AssetManagementQuarterlyFees
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.

+ References

No definition available.

+ Details

Name:	nen_InvestmentsInNumberOfLimitedPartnershipsAndLimitedLiabilityCompanies
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

Represents the number of employees other than the President having an ownership interest.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

Name:	nen_RelatedPartyTransactionBookkeepingAndAccountingServicesFee
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

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

- Definition

Represents the charge against earnings towards management fees associate 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

Name:	nen_RelatedPartyTransactionManagementFeeAsPercentageOfLinewt
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

Name:	nen_RelatedPartyTransactionManagementFeeAsPercentageOfPropertyRentalRevenueAndLaundryIncome
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

Name:	nen_RelatedPartyTransactionNumberOfAccountingStaff
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

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

- Definition

Represents the amount of rental commission expense charged against the earnings during the period.

+ References

No definition available.

+ Details

Name:	nen_RentalCommission
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=26872669&loc=d3e20235-122688

+ Details

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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=6414718&loc=d3e28014-114942

+ Details

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Namespace Prefix:	us-gaap_
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=6382943&loc=d3e33918-111571

+ Details

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Namespace Prefix:	us-gaap_
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=26872669&loc=d3e20235-122688

+ Details

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

-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 225

-Section 45

-Paragraph 3

-Subparagraph (k)

-URI http://asc.fasb.org/extlink&oid=6488370&loc=d3e13550-115849

+ Details

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Namespace Prefix:	us-gaap_
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 4

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 3

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-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

+ Details

Name:	us-gaap_RelatedPartyTransactionAmountsOfTransaction
Namespace Prefix:	us-gaap_
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

- Details

Name:	us-gaap_RelatedPartyTransactionLineItems
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Data Type:	xbrli:stringItemType
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RELATED PARTY TRANSACTIONS (Details) (USD $)	3 Months Ended		12 Months Ended
RELATED PARTY TRANSACTIONS (Details) (USD $)	Mar. 31, 2014 item	Mar. 31, 2013	Dec. 31, 2013
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	$ 427,000	$ 374,000
Repairs and maintenance	1,211,254	1,081,279
Administrative expense	530,567	452,619
Management fee	427,392	369,252
Number of limited partnerships and limited liability companies in which the entity has invested	9
Limited Partnerships \| Minimum
RELATED PARTY TRANSACTIONS
Percentage of ownership interest	40.00%
Limited Partnerships \| Maximum
RELATED PARTY TRANSACTIONS
Percentage of ownership interest	50.00%
General Partner or Management Company
RELATED PARTY TRANSACTIONS
Costs related to professional services	178,000	214,000
Repairs and maintenance	70,000
Administrative expense	82,000
Rental commission	6,000
Expenses for construction, architectural services and supervision of capital projects	20,000
Management Company
RELATED PARTY TRANSACTIONS
Reimbursement to related party for payroll transfers	866,000	752,000
Employer contributions in 401K plan	0		0
Number of accounting staff of related party providing bookkeeping and accounting functions	14
Fees for accounting and bookkeeping services	31,250	31,250
Fees for accounting and bookkeeping services per year	125,000
Number of employees having ownership interest	6
Hamilton Company
RELATED PARTY TRANSACTIONS
Management fee as percentage of gross receipts rental revenue	4.00%
Repairs and maintenance	29,000
Administrative expense	12,000
Amount paid to related party	201,000
Management fee	160,000
Dexter Park
RELATED PARTY TRANSACTIONS
Management fee as percentage of gross receipts rental revenue	2.00%
Administrative expense	54,543
President of Management Company
RELATED PARTY TRANSACTIONS
Quarterly fee for asset management consulting services	$ 18,750	$ 18,750
Harold Brown \| Minimum
RELATED PARTY TRANSACTIONS
Percentage of ownership interest	43.20%
Harold Brown \| Maximum
RELATED PARTY TRANSACTIONS
Percentage of ownership interest	60.00%