XML 62 R73.htm IDEA: XBRL DOCUMENT
v3.20.1

SUBSEQUENT EVENTS (Details) | 2 Months Ended | 12 Months Ended | 149 Months Ended |  |
--- | --- | --- | --- | --- | ---
Mar. 08, 2020 USD ($) $ / item shares | Dec. 31, 2019 USD ($) shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2019 USD ($) $ / item shares | Feb. 07, 2020 USD ($) | Dec. 20, 2019 USD ($)
Subsequent events |  |  |  |  |  |  |
Number of depository receipts repurchased | shares |  |  | 57,803 |  | 1,423,109 |  |
Repurchase price of depository receipts (in dollars per receipt) | $ / item |  |  |  |  | 28.31 |  |
Total cost of repurchase |  | $ 4,050,137 |  | $ 42,548 | $ 44,324,000 |  |
Units required to be repurchased (in shares) | shares |  | 2,408 |  | 23 |  |  |
57 Mill Street |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  | $ 31,000,000
Subsequent event |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Number of depository receipts repurchased | shares | 3,469 |  |  |  |  |  |
Repurchase price of depository receipts (in dollars per receipt) | $ / item | 62.01 |  |  |  |  |  |
Price per unit of depository receipts | $ / item | 1,860.30 |  |  |  |  |  |
Total cost of repurchase | $ 215,113 |  |  |  |  |  |
Term of debt |  |  |  |  |  | 15 years |
Mortgage amount |  |  |  |  |  | $ 6,175,000 |
Interest rate (as a percent) |  |  |  |  |  | 3.53% |
Loan balance |  |  |  |  |  | $ 2,390,000 |
Class B |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Number of depository receipts repurchased | shares |  |  |  |  | 3,530 |  |
Repurchase price of depository receipts (in dollars per receipt) | $ / item |  |  |  |  | 1,024.08 |  |
Total cost of repurchase |  | $ 769,458 |  | $ 8,084 |  |  |
Class B | Subsequent event |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Value of units required to be repurchased | 51,087 |  |  |  |  |  |
General Partnership |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Number of depository receipts repurchased | shares |  |  |  |  | 186 |  |
Total cost of repurchase |  | $ 40,498 | $ 40,498 | $ 426 |  |  |
General Partnership | Subsequent event |  |  |  |  |  |  |
Subsequent events |  |  |  |  |  |  |
Value of units required to be repurchased | $ 2,689 |  |  |  |  |  |

X
- Definition Represents the number of depository receipts repurchased under the equity repurchase program. + References No definition available. + Details
Name: | nen_PartnersCapitalAccountDepositoryReceiptsTreasury
Namespace Prefix: | nen_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the average price at which depository receipts are repurchased under the equity repurchase program. + References No definition available. + Details
Name: | nen_PartnersCapitalAccountDepositoryReceiptsTreasuryAverageRepurchasePricePerDepositoryReceipt
Namespace Prefix: | nen_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the cost per unit of depository receipts. + References No definition available. + Details
Name: | nen_PartnersCapitalAccountDepositoryReciptsTreasuryPricePerUnit
Namespace Prefix: | nen_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the value of the units required to be repurchased. + References No definition available. + Details
Name: | nen_UnitRepurchasesRequiredValue
Namespace Prefix: | nen_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_LongTermDebtTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Value of units that were previously issued and have been repurchased during the year. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 272 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6828210&loc=d3e70191-108054 + Details
Name: | us-gaap_PartnersCapitalAccountTreasuryUnitsPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Units that were previously issued and have been repurchased during the year. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 5 -Subparagraph (SAB TOPIC 4.F) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770 + Details
Name: | us-gaap_PartnersCapitalAccountUnitsTreasury
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nen_FiftySevenMillStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=nen_LimitedClassBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_GeneralPartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |