Represents the amount of allowance for doubtful accounts related to rents receivable.

No definition available.

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

- Definition

Represents the amount of amortization of deferred rents.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of annual rent to be receivable for leases to be expired.

+ References

No definition available.

+ Details

Name:	nen_OperatingLeasesAnnualBaseRentForExpiringLeases
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the deferred rental concessions on real estate properties.

+ References

No definition available.

+ Details

Name:	nen_OperatingLeasesDeferralOfRentalConcession
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the maximum period of non-cancellable operating leases.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of leases to be expired.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of annual base rent for leases to be expired.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of rental income related to commercial real estate property.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of rental income related to residential real estate property.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount resulting from recognizing rental income from non-cancelable commercial leases with future rental increases on a straight-line basis, which is included in rents receivable.

+ References

No definition available.

+ Details

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

- Definition

Represents the square feet area of rental properties for which leases are to be expired.

+ References

No definition available.

+ Details

Name:	nen_OperatingLeasesSquareFeetForExpiringLeases
Namespace Prefix:	nen_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

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

- Definition

Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6454179&loc=d3e41551-112718

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 23

-Subparagraph b(ii)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Details

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

- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

+ References

+ Details

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

- Definition

Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

+ References

+ Details

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

- Definition

Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

+ References

+ Details

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

- Definition

Future rental payments receivable within the third year from the balance sheet date under an operating lease.

+ References

+ Details

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

- Definition

Future rental payments receivable within the second year from the balance sheet date under an operating lease.

+ References

+ Details

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

- Definition

Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

+ References

+ Details

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

- Definition

Amount of contingent rental revenue recognized for the period under lease, based on the occurrences of an event or condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6454179&loc=d3e41551-112718

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 23

-Subparagraph b(iii)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

RENTAL INCOME (Details) (USD $)	9 Months Ended
RENTAL INCOME (Details) (USD $)	Sep. 30, 2013 sqft item	Sep. 30, 2012	Dec. 31, 2012
RENTAL INCOME
Percentage of rental income related to residential apartments and condominium units with leases of one year or less	92.00%
Maximum period of non-cancellable operating lease	1 year
Percentage of rental income related to commercial properties	8.00%
Minimum future rental income
2014	$ 2,499,000
2015	1,929,000
2016	1,734,000
2017	903,000
2018	583,000
Thereafter	505,000
Commercial Property Leases	8,153,000
Aggregate contingent rentals from continuing operations	489,000	477,000
RENTAL INCOME
Annual base rent for expiring leases	2,472,903
Total square feet for expiring leases	94,082
Total number of leases expiring	40
Percentage of annual base rent for expiring leases	100.00%
Allowance for doubtful rent receivable	556,000		381,000
Recognizing rental income from non-cancelable commercial leases with future rental increases on a straight-line basis	311,000
Deferred rental concession	16,000
Amortization of deferred rents	1,600
Through September 30, 2014
RENTAL INCOME
Annual base rent for expiring leases	322,864
Total square feet for expiring leases	17,551
Total number of leases expiring	11
Percentage of annual base rent for expiring leases	13.00%
Through September 30, 2015
RENTAL INCOME
Annual base rent for expiring leases	422,746
Total square feet for expiring leases	18,982
Total number of leases expiring	7
Percentage of annual base rent for expiring leases	17.00%
Through September 30, 2016
RENTAL INCOME
Annual base rent for expiring leases	623,398
Total square feet for expiring leases	23,082
Total number of leases expiring	5
Percentage of annual base rent for expiring leases	25.00%
Through September 30, 2017
RENTAL INCOME
Annual base rent for expiring leases	519,132
Total square feet for expiring leases	17,542
Total number of leases expiring	7
Percentage of annual base rent for expiring leases	21.00%
Through September 30, 2018
RENTAL INCOME
Annual base rent for expiring leases	254,932
Total square feet for expiring leases	8,219
Total number of leases expiring	6
Percentage of annual base rent for expiring leases	10.00%
Through September 30, 2019
RENTAL INCOME
Annual base rent for expiring leases	123,200
Total square feet for expiring leases	3,850
Total number of leases expiring	1
Percentage of annual base rent for expiring leases	5.00%
Through September 30, 2020
RENTAL INCOME
Annual base rent for expiring leases	141,831
Total square feet for expiring leases	3,056
Total number of leases expiring	2
Percentage of annual base rent for expiring leases	6.00%
Through September 30, 2021
RENTAL INCOME
Annual base rent for expiring leases	64,800
Total square feet for expiring leases	1,800
Total number of leases expiring	1
Percentage of annual base rent for expiring leases	3.00%
Through September 30, 2022
RENTAL INCOME
Annual base rent for expiring leases	0
Total square feet for expiring leases	0
Total number of leases expiring	0
Percentage of annual base rent for expiring leases	0.00%
Through September 30, 2023
RENTAL INCOME
Annual base rent for expiring leases	$ 0
Total square feet for expiring leases	0
Total number of leases expiring	0
Percentage of annual base rent for expiring leases	0.00%