Represents the percentage of debt extinguishment costs to be paid

No definition available.

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Namespace Prefix:	nen_
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Balance Type:	na
Period Type:	instant

- Definition

Represents the amortization period of mortgage loan principal payments following any initial period requiring only interest payments.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

This element represents the aggregate cost of investments 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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

- 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)
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+ Details

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

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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+ Details

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

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

- Definition

Total distributions to each class of partners (i.e., general, limited and preferred partners).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 5
-Subparagraph (SAB Topic 4.F)
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-Paragraph 1
-Subparagraph (SX 210.3-04)
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
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-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nen_HamiltonParkTowersLLCMember
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- Details

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- Details

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- Details

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INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Dexter) (Details)			1 Months Ended	3 Months Ended	6 Months Ended
	May 31, 2018 USD ($)	Oct. 28, 2009 USD ($) item	Feb. 28, 2007 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($) item	Dec. 31, 2017 USD ($)	Mar. 01, 2017 USD ($)	Oct. 03, 2005 USD ($) item
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Investments in joint venture				$ 2,298,588	$ 2,298,588	$ 9,029,233	$ 7,212,044
Number of units \| item						1,033
Outstanding amount of mortgage				253,185,372	253,185,372		$ 233,221,258
Distribution to the Partnership					2,238,962	$ 2,239,168
Dexter Park
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Investments in joint venture		$ 15,925,000				$ 2,824,225
Ownership interest (as a percent)		40.00%				40.00%
Number of units \| item		409				409
Outstanding amount of mortgage	$ 82,000,000			125,000,000	$ 125,000,000
Purchase price of investments		$ 129,500,000
Distribution to the Partnership	$ 41,200,000
Dexter Park \| Mortgages payable
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Interest rate (as a percent)		5.57%
Period for which the entity is required to make interest only payments		2 years
Amortization period of debt		30 years
Borrowings		$ 89,914,000
Hamilton Bay Apts
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Investments in joint venture						$ 2,473,933			$ 2,500,000
Ownership interest (as a percent)						50.00%			50.00%
Number of units \| item						48			168
Interest rate (as a percent)			5.57%
Period for which the entity is required to make interest only payments			5 years
Amortization period of debt			30 years
Purchase price of investments									$ 30,875,000
Borrowings			$ 4,750,000
Hamilton Bay Apts \| Mortgages payable
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Outstanding amount of mortgage								$ 2,222,000
John Hancock \| Dexter Park
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Interest rate (as a percent)	3.99%
Defeasance cost				$ 3,830,000
Defeasance cost (as a percent)				40.00%	40.00%
Loan amount	$ 125,000,000
General Partnership
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Distribution to the Partnership					$ 22,390	$ 22,392
General Partnership \| Dexter Park
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Distribution to the Partnership	$ 16,500,000
General Partnership \| John Hancock \| Dexter Park
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Defeasance cost				$ 1,532,000
Residential buildings
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Number of units \| item						1,030
Residential buildings \| Dexter Park
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Number of units \| item						409
Residential buildings \| Hamilton Bay Apts
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES
Number of units \| item						48