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INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Details 3) (USD $) | 3 Months Ended | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Nov. 30, 2001 | Mar. 02, 2005 | Oct. 03, 2005 | Sep. 30, 2004 | Aug. 31, 2004 | Oct. 28, 2009
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | $ 42,205,644 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue | $ 37,961,599 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue | $ 34,784,130 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 426,675 us-gaap_OtherRealEstateRevenue | 402,953 us-gaap_OtherRealEstateRevenue | 385,040 us-gaap_OtherRealEstateRevenue |  |  |  |  |  |
Total Revenues | 10,810,827 us-gaap_Revenues | 10,643,029 us-gaap_Revenues | 10,560,535 us-gaap_Revenues | 10,617,928 us-gaap_Revenues | 10,374,345 us-gaap_Revenues | 9,967,752 us-gaap_Revenues | 9,002,762 us-gaap_Revenues | 9,019,693 us-gaap_Revenues | 42,632,319 us-gaap_Revenues | 38,364,552 us-gaap_Revenues | 35,169,170 us-gaap_Revenues |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 2,206,483 us-gaap_GeneralAndAdministrativeExpense | 2,116,527 us-gaap_GeneralAndAdministrativeExpense | 1,813,150 us-gaap_GeneralAndAdministrativeExpense |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 10,551,527 us-gaap_DepreciationDepletionAndAmortization | 8,377,902 us-gaap_DepreciationDepletionAndAmortization | 6,012,755 us-gaap_DepreciationDepletionAndAmortization |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 4,668,196 us-gaap_OtherCostOfOperatingRevenue | 4,201,928 us-gaap_OtherCostOfOperatingRevenue | 3,580,690 us-gaap_OtherCostOfOperatingRevenue |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 430,949 us-gaap_LeaseAndRentalExpense | 202,787 us-gaap_LeaseAndRentalExpense | 180,574 us-gaap_LeaseAndRentalExpense |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 6,608,290 us-gaap_CostOfPropertyRepairsAndMaintenance | 5,815,264 us-gaap_CostOfPropertyRepairsAndMaintenance | 5,075,037 us-gaap_CostOfPropertyRepairsAndMaintenance |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 5,519,432 us-gaap_RealEstateTaxesAndInsurance | 4,948,569 us-gaap_RealEstateTaxesAndInsurance | 4,299,169 us-gaap_RealEstateTaxesAndInsurance |  |  |  |  |  |
Total Expenses | 7,924,264 us-gaap_OperatingExpenses | 7,916,421 us-gaap_OperatingExpenses | 7,835,735 us-gaap_OperatingExpenses | 8,053,306 us-gaap_OperatingExpenses | 7,654,735 us-gaap_OperatingExpenses | 7,484,223 us-gaap_OperatingExpenses | 6,113,940 us-gaap_OperatingExpenses | 5,980,237 us-gaap_OperatingExpenses | 31,729,726 us-gaap_OperatingExpenses | 27,233,135 us-gaap_OperatingExpenses | 22,389,427 us-gaap_OperatingExpenses |  |  |  |  |  |
Income Before Other Income | 2,886,563 us-gaap_OperatingIncomeLoss | 2,726,608 us-gaap_OperatingIncomeLoss | 2,724,800 us-gaap_OperatingIncomeLoss | 2,564,622 us-gaap_OperatingIncomeLoss | 2,719,610 us-gaap_OperatingIncomeLoss | 2,483,529 us-gaap_OperatingIncomeLoss | 2,888,822 us-gaap_OperatingIncomeLoss | 3,039,456 us-gaap_OperatingIncomeLoss | 10,902,593 us-gaap_OperatingIncomeLoss | 11,131,417 us-gaap_OperatingIncomeLoss | 12,779,743 us-gaap_OperatingIncomeLoss |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (9,553,200)us-gaap_InterestExpense | (8,013,109)us-gaap_InterestExpense | (7,695,232)us-gaap_InterestExpense |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 754 us-gaap_InvestmentIncomeInterest | 1,118 us-gaap_InvestmentIncomeInterest | 2,216 us-gaap_InvestmentIncomeInterest |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  |  | 3,678,839 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax |  |  |  |  |  |  |
Total Other Income (loss) | (2,295,307)us-gaap_NonoperatingIncomeExpense | (2,545,121)us-gaap_NonoperatingIncomeExpense | (2,443,079)us-gaap_NonoperatingIncomeExpense | (2,594,236)us-gaap_NonoperatingIncomeExpense | (2,401,979)us-gaap_NonoperatingIncomeExpense | (2,515,749)us-gaap_NonoperatingIncomeExpense | (2,098,628)us-gaap_NonoperatingIncomeExpense | (2,157,562)us-gaap_NonoperatingIncomeExpense | (9,877,743)us-gaap_NonoperatingIncomeExpense | (9,173,918)us-gaap_NonoperatingIncomeExpense | (9,179,293)us-gaap_NonoperatingIncomeExpense |  |  |  |  |  |
Net Income (Loss) | 591,256 us-gaap_NetIncomeLoss | 181,487 us-gaap_NetIncomeLoss | 281,721 us-gaap_NetIncomeLoss | (29,614)us-gaap_NetIncomeLoss | 317,518 us-gaap_NetIncomeLoss | (32,874)us-gaap_NetIncomeLoss | 4,469,116 us-gaap_NetIncomeLoss | 901,625 us-gaap_NetIncomeLoss | 1,024,850 us-gaap_NetIncomeLoss | 5,655,385 us-gaap_NetIncomeLoss | 3,633,798 us-gaap_NetIncomeLoss |  |  |  |  |  |
Hamilton Essex 81 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 1,409,443 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 1,362,012 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 1,270,141 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 17,634 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 17,549 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 15,363 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 1,427,077 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 1,379,562 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 1,285,504 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 32,908 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 18,330 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 15,237 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 434,834 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 428,609 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 409,488 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 57,914 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 55,813 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 55,308 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 121,354 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 114,778 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 112,172 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 11,900 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 11,106 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 18,350 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 156,321 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 123,702 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 118,786 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 228,556 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 216,560 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 197,566 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 1,043,787 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 968,897 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 926,908 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 383,290 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 410,665 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 358,596 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (483,197)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (488,369)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (497,631)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (483,197)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (488,369)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (497,631)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (99,907)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (77,704)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (139,035)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |  |  |
Hamilton Essex 81 | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (49,954)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (38,852)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | (69,517)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |
Hamilton Essex 81 | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssex81LLCMember |  |  |  |  |  |  |  |
Hamilton Essex Development |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 291,517 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 287,410 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 287,537 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 0 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 291,517 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 287,410 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 287,537 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 1,530 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 1,370 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 1,749 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 11,287 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 9,803 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 11,638 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 11,661 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 11,496 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 11,502 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 0 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 0 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 3,810 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 4,950 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 5,475 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 53,556 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 49,192 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 49,237 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 81,844 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 76,812 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 79,600 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 209,673 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 210,598 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 207,937 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (55,877)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | (58,093)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | (60,451)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (55,877)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | (58,093)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | (60,451)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | 153,796 us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 152,505 us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 147,486 us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
Hamilton Essex Development | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 76,898 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 76,252 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 73,743 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |
Hamilton Essex Development | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonEssexDevelopmentLLCMember |  |  |  |  |  |  |  |
345 Franklin |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 1,347,653 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 1,258,313 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 1,178,712 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 1,547 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 2,683 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 1,206 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 1,349,200 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 1,260,996 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 1,179,918 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 41,319 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 23,813 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 27,942 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 401,813 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 428,003 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 441,704 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 55,776 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 51,706 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 48,596 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 60,695 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 68,364 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 62,277 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 13,870 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 3,788 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 5,326 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 67,219 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 86,844 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 82,052 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 118,103 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 114,669 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 106,785 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 758,795 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 777,187 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 774,681 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 590,405 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 483,809 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 405,237 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (391,451)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (453,197)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (486,051)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 26 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 48 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |  |  |
Other Income (Expenses) |  |  |  |  |  |  |  |  |  | (68,588)us-gaap_OtherNonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (391,451)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (521,759)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (486,003)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | 198,954 us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (37,950)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (80,766)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |
345 Franklin | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 99,477 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (18,975)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | (40,383)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |
345 Franklin | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Franklin345LLCMember |  |  |  |  |  |  |  |
Hamilton 1025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 933,315 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 896,256 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 861,998 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 0 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 933,315 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 896,256 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 861,998 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 8,550 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 9,552 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 5,142 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 240,808 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 240,658 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 256,696 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 37,388 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 36,066 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 34,517 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 1,023 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 1,150 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 816 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 9,701 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 5,378 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 6,815 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 326,111 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 320,348 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 320,997 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 158,129 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 151,971 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 145,755 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 781,710 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 765,121 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 770,738 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 151,605 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 131,134 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 91,260 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (280,385)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (284,257)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (288,470)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 21 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 8 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 74 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (280,364)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (284,249)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (288,395)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (128,759)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (153,114)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (197,135)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |
Hamilton 1025 | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (64,380)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (76,557)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | (98,567)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |
Hamilton 1025 | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_Hamilton1025LLCMember |  |  |  |  |  |  |  |
Hamilton Bay Sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 187,228 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 261,949 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 235,061 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 0 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 187,228 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 261,949 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 235,061 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 4,361 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 10,134 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 7,553 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 36,183 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 80,697 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 82,287 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 7,545 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 10,538 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 9,894 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 1,058 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 2,234 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 1,251 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 1,238 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 1,425 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 1,894 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 84,460 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 94,640 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 70,812 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 36,624 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 42,765 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 46,017 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 171,469 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 242,433 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 219,707 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 15,759 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 19,516 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 15,354 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (596)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (73,819)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (98,361)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 159 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 215 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 468 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 3,258 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 6,180 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 475,335 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | 475,207 us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (70,402)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (91,966)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | 490,966 us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (50,886)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (76,612)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |  |  |
Hamilton Bay Sales | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 245,483 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (25,443)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | (38,306)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |
Hamilton Bay Sales | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayLLCMember |  |  |  |  |  |  |  |
Hamilton Bay Apartments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 943,525 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 911,845 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 886,122 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 0 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 943,525 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 911,845 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 886,122 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 18,053 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 16,291 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 34,600 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 300,634 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 307,546 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 297,737 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 38,392 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 35,831 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 34,659 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 1,801 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 1,343 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 1,190 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 6,563 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 10,986 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 4,053 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 294,811 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 295,144 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 273,652 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 158,858 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 146,870 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 161,137 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 819,112 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 814,012 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 807,027 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 124,413 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 97,833 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 79,095 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (263,656)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (267,228)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (271,283)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (263,656)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (267,228)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (271,283)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (139,243)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (169,395)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (192,188)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |
Hamilton Bay Apartments | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (69,622)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (84,697)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | (96,094)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |
Hamilton Bay Apartments | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonBayApartmentsLLCMember |  |  |  |  |  |  |  |
Hamilton Minuteman |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 919,874 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 858,492 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 809,707 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 1,731 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 675 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 2,435 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 921,605 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 859,167 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 812,142 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 8,823 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 6,206 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 7,825 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 322,642 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 318,095 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 317,231 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 37,869 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 34,129 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 32,615 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 81,659 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 83,143 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 73,092 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 8,475 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 6,350 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 3,538 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 79,215 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 69,057 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 57,448 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 119,406 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 121,442 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 102,505 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 658,089 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 638,423 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 594,254 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 263,516 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 220,744 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 217,888 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (308,646)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (312,507)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (317,448)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (308,646)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (312,507)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (317,448)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (45,130)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (91,763)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (99,560)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |
Hamilton Minuteman | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (22,565)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (45,882)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | (49,780)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |
Hamilton Minuteman | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonMinutemanLLCMember |  |  |  |  |  |  |  |
Hamilton on Main Apts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 2,931,793 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,753,120 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,623,994 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 38,668 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 37,192 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 20,952 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 2,970,461 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,790,312 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,644,946 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 54,694 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 38,144 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 46,400 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 958,081 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 948,478 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 957,452 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 116,157 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 112,749 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 104,807 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 399,600 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 347,382 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 341,054 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 23,311 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 6,273 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 10,974 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 395,608 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 389,671 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 380,605 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 367,278 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 342,995 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 337,256 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 2,314,729 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,185,692 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 2,178,549 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 655,732 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 604,620 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 466,397 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (800,881)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (822,109)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (840,874)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (800,881)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (822,109)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (840,874)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (145,149)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (217,489)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (374,477)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |
Hamilton on Main Apts | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (72,575)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (108,744)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | (187,239)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Percentage of ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |
Hamilton on Main Apts | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonOnMainLLCMember |  |  |  |  |  |  |  |
Dexter Park |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 13,658,064 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 12,851,259 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 12,202,615 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 100,935 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 94,715 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 98,042 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 13,758,999 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 12,945,974 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 12,300,657 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 226,551 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 245,444 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 219,218 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 5,406,157 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 5,778,427 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 5,733,920 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 289,170 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 271,505 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 261,355 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 1,233,796 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 1,056,919 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 1,006,570 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 177,251 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 105,593 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 74,705 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 1,181,497 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 1,051,832 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 880,103 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 1,462,398 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 1,529,605 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 1,485,297 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 9,976,820 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 10,039,324 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 9,661,169 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 3,782,179 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 2,906,650 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 2,639,488 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (4,952,328)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (5,016,659)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (5,092,838)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 57 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 0 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 0 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (4,952,328)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (5,016,602)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (5,092,838)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (1,170,149)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (2,109,952)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (2,453,350)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |  |  |
Percentage of ownership interest |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember
Dexter Park | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 0 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |  |  |
Dexter Park | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (468,061)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (843,981)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | (981,340)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Percentage of ownership interest | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = nen_HamiltonParkTowersLLCMember |  |  |  |  |  |
Total |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rental income |  |  |  |  |  |  |  |  | 22,622,412 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 21,440,655 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 20,355,887 us-gaap_OperatingLeasesIncomeStatementLeaseRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Laundry and sundry income |  |  |  |  |  |  |  |  | 160,515 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 152,814 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 137,999 us-gaap_OtherRealEstateRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Total Revenues |  |  |  |  |  |  |  |  | 22,782,927 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 21,593,469 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 20,493,885 us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Administrative |  |  |  |  |  |  |  |  | 396,789 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 369,284 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 365,666 us-gaap_GeneralAndAdministrativeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  | 8,112,439 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 8,540,316 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 8,508,153 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Management fees |  |  |  |  |  |  |  |  | 651,872 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 619,833 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 593,253 us-gaap_ProfessionalAndContractServicesExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Operating |  |  |  |  |  |  |  |  | 1,900,986 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 1,675,312 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 1,598,421 us-gaap_OtherCostOfOperatingRevenue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Renting |  |  |  |  |  |  |  |  | 252,309 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 150,898 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 125,655 us-gaap_LeaseAndRentalExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Repairs and maintenance |  |  |  |  |  |  |  |  | 2,589,052 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 2,436,188 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 2,189,930 us-gaap_CostOfPropertyRepairsAndMaintenance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Taxes and insurance |  |  |  |  |  |  |  |  | 2,702,908 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 2,716,069 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 2,631,555 us-gaap_RealEstateTaxesAndInsurance / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Total Expenses |  |  |  |  |  |  |  |  | 16,606,355 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 16,507,900 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 16,012,632 us-gaap_OperatingExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Income Before Other Income |  |  |  |  |  |  |  |  | 6,176,572 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 5,085,569 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 4,481,253 us-gaap_OperatingIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | (7,537,017)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (7,776,238)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (7,953,407)us-gaap_InterestExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Interest Income |  |  |  |  |  |  |  |  | 21 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 250 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 337 us-gaap_InvestmentIncomeInterest / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Interest Income from Note |  |  |  |  |  |  |  |  | 468 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 3,258 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | 6,180 us-gaap_InterestIncomeOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Gain on Sale of Real Estate |  |  |  |  |  |  |  |  | 475,335 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |  |  |
Other Income (Expenses) |  |  |  |  |  |  |  |  |  | (68,588)us-gaap_OtherNonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |  |
Total Other Income (loss) |  |  |  |  |  |  |  |  | (7,061,193)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (7,841,318)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (7,946,890)us-gaap_NonoperatingIncomeExpense / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Net Income (Loss) |  |  |  |  |  |  |  |  | (884,621)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (2,755,749)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (3,465,636)us-gaap_NetIncomeLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | (325,297)nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (1,166,879)nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (1,487,483)nen_NetIncomeLossProportionateShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Total | NERA 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | 142,764 nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (322,898)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | (506,143)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership50PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |
Total | NERA 40% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate share of net income (loss) |  |  |  |  |  |  |  |  | $ (468,061)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | $ (843,981)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember | $ (981,340)nen_NetIncomeLossProportionateShare / nen_PartnershipOwnershipAxis = nen_NewEnglandRealtyAssociatesLimitedPartnership40PercentOwnershipMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = us-gaap_EquityMethodInvestmentsMember |  |  |  |  |  |

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