Represents the useful life of constituents of rental properties.

No definition available.

Name:	nen_RealEstateInvestmentPropertyUsefulLife
Namespace Prefix:	nen_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(3))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 7

+ Details

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

- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

+ Details

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

- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

+ Details

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

RENTAL PROPERTIES (Details) - 10Q (USD $)	3 Months Ended
RENTAL PROPERTIES (Details) - 10Q (USD $)	Mar. 31, 2015	Dec. 31, 2014
Rental properties
Total fixed assets	$ 225,894,113	$ 225,021,946
Less: Accumulated depreciation	(78,320,385)	(75,905,862)
Total fixed assets, net	147,573,728us-gaap_RealEstateInvestmentPropertyNet	149,116,084us-gaap_RealEstateInvestmentPropertyNet
Land, improvements and parking lots
Rental properties
Total fixed assets, net	44,541,471	44,541,471
Land, improvements and parking lots \| Minimum
Rental properties
Useful Life	15 years
Land, improvements and parking lots \| Maximum
Rental properties
Useful Life	40 years
Buildings and Improvements
Rental properties
Total fixed assets, net	153,342,470	153,059,430
Buildings and Improvements \| Minimum
Rental properties
Useful Life	15 years
Buildings and Improvements \| Maximum
Rental properties
Useful Life	40 years
Kitchen cabinets
Rental properties
Total fixed assets, net	7,080,552	6,865,348
Kitchen cabinets \| Minimum
Rental properties
Useful Life	5 years
Kitchen cabinets \| Maximum
Rental properties
Useful Life	10 years
Carpets
Rental properties
Total fixed assets, net	6,481,927	6,341,227
Carpets \| Minimum
Rental properties
Useful Life	5 years
Carpets \| Maximum
Rental properties
Useful Life	10 years
Air conditioning
Rental properties
Total fixed assets, net	705,116	705,116
Air conditioning \| Minimum
Rental properties
Useful Life	5 years
Air conditioning \| Maximum
Rental properties
Useful Life	10 years
Laundry equipment
Rental properties
Total fixed assets, net	153,052	147,721
Laundry equipment \| Minimum
Rental properties
Useful Life	5 years
Laundry equipment \| Maximum
Rental properties
Useful Life	7 years
Elevators
Rental properties
Total fixed assets, net	1,139,296	1,139,296
Elevators \| Minimum
Rental properties
Useful Life	20 years
Elevators \| Maximum
Rental properties
Useful Life	40 years
Swimming pools
Rental properties
Total fixed assets, net	444,629	444,629
Swimming pools \| Minimum
Rental properties
Useful Life	10 years
Swimming pools \| Maximum
Rental properties
Useful Life	30 years
Equipment
Rental properties
Total fixed assets, net	5,556,712	5,491,992
Equipment \| Minimum
Rental properties
Useful Life	5 years
Equipment \| Maximum
Rental properties
Useful Life	7 years
Motor vehicles
Rental properties
Total fixed assets, net	130,859	130,563
Useful Life	5 years
Fences
Rental properties
Total fixed assets, net	24,670	24,670
Fences \| Minimum
Rental properties
Useful Life	5 years
Fences \| Maximum
Rental properties
Useful Life	15 years
Furniture and fixtures
Rental properties
Total fixed assets, net	6,072,922	5,910,046
Furniture and fixtures \| Minimum
Rental properties
Useful Life	5 years
Furniture and fixtures \| Maximum
Rental properties
Useful Life	7 years
Smoke alarms
Rental properties
Total fixed assets, net	$ 220,437	$ 220,437
Smoke alarms \| Minimum
Rental properties
Useful Life	5 years
Smoke alarms \| Maximum
Rental properties
Useful Life	7 years
Residential and mixed-use properties
RENTAL PROPERTIES
Number of units	2,412
Number of properties	20
Residential and mixed-use properties \| Partially owned properties
RENTAL PROPERTIES
Number of units	790
Number of properties	9
Residential and mixed-use properties \| Partially owned properties \| Minimum
RENTAL PROPERTIES
Percentage of ownership interest	40.00%
Residential and mixed-use properties \| Partially owned properties \| Maximum
RENTAL PROPERTIES
Percentage of ownership interest	50.00%
Condominium
RENTAL PROPERTIES
Number of units	19