| IRS990/AccountantCompileOrReviewInd | 0 | false |
| IRS990/AccountsPayableAccrExpnssGrp/BOYAmt | 0 | 1194228 |
| IRS990/AccountsPayableAccrExpnssGrp/EOYAmt | 0 | 1118496 |
| IRS990/AccountsReceivableGrp/BOYAmt | 0 | 0 |
| IRS990/AccountsReceivableGrp/EOYAmt | 0 | 0 |
| IRS990/ActivitiesConductedPrtshpInd | 0 | false |
| IRS990/ActivityOrMissionDesc | 0 | See Schedule O |
| IRS990/AdvertisingGrp/TotalAmt | 0 | 0 |
| IRS990/AnnualDisclosureCoveredPrsnInd | 0 | true |
| IRS990/AuditCommitteeInd | 0 | true |
| IRS990/BenefitsToMembersGrp/TotalAmt | 0 | 0 |
| IRS990/BooksInCareOfDetail/PersonNm | 0 | MAHENDRA JAGMOHAN |
| IRS990/BooksInCareOfDetail/PhoneNum | 0 | 6466054103 |
| IRS990/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | 150 E 42ND STREET 5TH FLOOR |
| IRS990/BooksInCareOfDetail/USAddress/CityNm | 0 | NEW YORK |
| IRS990/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | NY |
| IRS990/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 10017 |
| IRS990/BusinessRlnWithFamMemInd | 0 | false |
| IRS990/BusinessRlnWithOfficerEntInd | 0 | false |
| IRS990/BusinessRlnWithOrgMemInd | 0 | false |
| IRS990/CapStkTrPrinCurrentFundsGrp/BOYAmt | 0 | 0 |
| IRS990/CapStkTrPrinCurrentFundsGrp/EOYAmt | 0 | 0 |
| IRS990/CashNonInterestBearingGrp/BOYAmt | 0 | 3940377 |
| IRS990/CashNonInterestBearingGrp/EOYAmt | 0 | 5422609 |
| IRS990/ChangeToOrgDocumentsInd | 0 | false |
| IRS990/CntrctRcvdGreaterThan100KCnt | 0 | 1 |
| IRS990/CollectionsOfArtInd | 0 | false |
| IRS990/CompCurrentOfcrDirectorsGrp/TotalAmt | 0 | 0 |
| IRS990/CompDisqualPersonsGrp/TotalAmt | 0 | 0 |
| IRS990/CompensationFromOtherSrcsInd | 0 | false |
| IRS990/CompensationProcessCEOInd | 0 | false |
| IRS990/CompensationProcessOtherInd | 0 | false |
| IRS990/ConferencesMeetingsGrp/TotalAmt | 0 | 0 |
| IRS990/ConflictOfInterestPolicyInd | 0 | true |
| IRS990/ConservationEasementsInd | 0 | false |
| IRS990/ConsolidatedAuditFinclStmtInd | 0 | false |
| IRS990/ContractorCompensationGrp/CompensationAmt | 0 | 1000000 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 0 | 200 MADISON AVENUE |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 0 | NEW YORK |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 0 | NY |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 0 | 10016 |
| IRS990/ContractorCompensationGrp/ContractorName/PersonNm | 0 | ROSE ASSOCIATES |
| IRS990/ContractorCompensationGrp/ServicesDesc | 0 | real estate mgmt |
| IRS990/CreditCounselingInd | 0 | false |
| IRS990/CYBenefitsPaidToMembersAmt | 0 | 0 |
| IRS990/CYContributionsGrantsAmt | 0 | 0 |
| IRS990/CYGrantsAndSimilarPaidAmt | 0 | 639337 |
| IRS990/CYInvestmentIncomeAmt | 0 | 107018 |
| IRS990/CYOtherExpensesAmt | 0 | 25183399 |
| IRS990/CYOtherRevenueAmt | 0 | 373376 |
| IRS990/CYProgramServiceRevenueAmt | 0 | 27795867 |
| IRS990/CYRevenuesLessExpensesAmt | 0 | 2453525 |
| IRS990/CYSalariesCompEmpBnftPaidAmt | 0 | 0 |
| IRS990/CYTotalExpensesAmt | 0 | 25822736 |
| IRS990/CYTotalFundraisingExpenseAmt | 0 | 0 |
| IRS990/CYTotalProfFndrsngExpnsAmt | 0 | 0 |
| IRS990/CYTotalRevenueAmt | 0 | 28276261 |
| IRS990/DecisionsSubjectToApprovaInd | 0 | false |
| IRS990/DeductibleArtContributionInd | 0 | false |
| IRS990/DeductibleNonCashContriInd | 0 | false |
| IRS990/DeferredRevenueGrp/BOYAmt | 0 | 0 |
| IRS990/DeferredRevenueGrp/EOYAmt | 0 | 0 |
| IRS990/DelegationOfMgmtDutiesInd | 0 | false |
| IRS990/DepreciationDepletionGrp/ProgramServicesAmt | 0 | 6155593 |
| IRS990/DepreciationDepletionGrp/TotalAmt | 0 | 6155593 |
| IRS990/Desc | 0 | MSMC RESIDENTIAL REALTY LLC SUPPORTS ITS MEMBER CORPORATIONS BY ACQUIRING, OWNING, FINANCING, OPERATING AND DISPOSING OF REAL ESTATE PRIMARILY FOR THE USE OF STAFF HOUSING. |
| IRS990/DescribedInSection501c3Ind | 0 | true |
| IRS990/DisregardedEntityInd | 0 | false |
| IRS990/DocumentRetentionPolicyInd | 0 | true |
| IRS990/DonorAdvisedFundInd | 0 | false |
| IRS990/ElectionOfBoardMembersInd | 0 | true |
| IRS990/EmployeeCnt | 0 | 0 |
| IRS990/EngagedInExcessBenefitTransInd | 0 | false |
| IRS990/EscrowAccountLiabilityGrp/BOYAmt | 0 | 0 |
| IRS990/EscrowAccountLiabilityGrp/EOYAmt | 0 | 0 |
| IRS990/ExpenseAmt | 0 | 24390605 |
| IRS990/FamilyOrBusinessRlnInd | 0 | false |
| IRS990/FederalGrantAuditRequiredInd | 0 | false |
| IRS990/FeesForServicesAccountingGrp/ManagementAndGeneralAmt | 0 | 40000 |
| IRS990/FeesForServicesAccountingGrp/TotalAmt | 0 | 40000 |
| IRS990/FeesForServicesLegalGrp/ManagementAndGeneralAmt | 0 | 106618 |
| IRS990/FeesForServicesLegalGrp/TotalAmt | 0 | 106618 |
| IRS990/FeesForServicesLobbyingGrp/TotalAmt | 0 | 0 |
| IRS990/FeesForServicesManagementGrp/ManagementAndGeneralAmt | 0 | 1000000 |
| IRS990/FeesForServicesManagementGrp/TotalAmt | 0 | 1000000 |
| IRS990/FeesForServicesOtherGrp/ProgramServicesAmt | 0 | 34911 |
| IRS990/FeesForServicesOtherGrp/TotalAmt | 0 | 34911 |
| IRS990/FeesForServicesProfFundraising/TotalAmt | 0 | 0 |
| IRS990/FeesForSrvcInvstMgmntFeesGrp/TotalAmt | 0 | 0 |
| IRS990/ForeignActivitiesInd | 0 | false |
| IRS990/ForeignFinancialAccountInd | 0 | false |
| IRS990/ForeignGrantsGrp/TotalAmt | 0 | 0 |
| IRS990/ForeignOfficeInd | 0 | false |
| IRS990/Form8282PropertyDisposedOfInd | 0 | false |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 0 | 64.5 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 0 | 0.5 |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 0 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 0 | X |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 0 | 57964 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 0 | DONALD T SCANLON 1 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 0 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 0 | 1721029 |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 0 | PRESIDENT AND TRUSTEE |
| IRS990/Form990ProvidedToGvrnBodyInd | 0 | true |
| IRS990/FormationYr | 0 | 2003 |
| IRS990/FormerOfcrEmployeesListedInd | 0 | false |
| IRS990/FSAuditedBasisGrp/SeparateBasisFinclStmtInd | 0 | X |
| IRS990/FSAuditedInd | 0 | true |
| IRS990/FundraisingActivitiesInd | 0 | false |
| IRS990/GamingActivitiesInd | 0 | false |
| IRS990/GoverningBodyVotingMembersCnt | 0 | 3 |
| IRS990/GrantAmt | 0 | 639337 |
| IRS990/GrantsPayableGrp/BOYAmt | 0 | 0 |
| IRS990/GrantsPayableGrp/EOYAmt | 0 | 0 |
| IRS990/GrantsToDomesticIndividualsGrp/TotalAmt | 0 | 0 |
| IRS990/GrantsToDomesticOrgsGrp/ProgramServicesAmt | 0 | 639337 |
| IRS990/GrantsToDomesticOrgsGrp/TotalAmt | 0 | 639337 |
| IRS990/GrantsToIndividualsInd | 0 | false |
| IRS990/GrantsToOrganizationsInd | 0 | true |
| IRS990/GrantToRelatedPersonInd | 0 | false |
| IRS990/GrossReceiptsAmt | 0 | 28276261 |
| IRS990/GroupReturnForAffiliatesInd | 0 | false |
| IRS990/IncludeFIN48FootnoteInd | 0 | false |
| IRS990/IncmFromInvestBondProceedsGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/IndependentAuditFinclStmtInd | 0 | true |
| IRS990/IndependentVotingMemberCnt | 0 | 0 |
| IRS990/IndivRcvdGreaterThan100KCnt | 0 | 0 |
| IRS990/IndoorTanningServicesInd | 0 | false |
| IRS990/InfoInScheduleOPartVIInd | 0 | X |
| IRS990/InformationTechnologyGrp/TotalAmt | 0 | 0 |
| IRS990/InsuranceGrp/ManagementAndGeneralAmt | 0 | 285513 |
| IRS990/InsuranceGrp/TotalAmt | 0 | 285513 |
| IRS990/IntangibleAssetsGrp/BOYAmt | 0 | 0 |
| IRS990/IntangibleAssetsGrp/EOYAmt | 0 | 0 |
| IRS990/InterestGrp/ProgramServicesAmt | 0 | 3984133 |
| IRS990/InterestGrp/TotalAmt | 0 | 3984133 |
| IRS990/InventoriesForSaleOrUseGrp/BOYAmt | 0 | 0 |
| IRS990/InventoriesForSaleOrUseGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentIncomeGrp/ExclusionAmt | 0 | 107018 |
| IRS990/InvestmentIncomeGrp/TotalRevenueColumnAmt | 0 | 107018 |
| IRS990/InvestmentInJointVentureInd | 0 | false |
| IRS990/InvestmentsOtherSecuritiesGrp/BOYAmt | 0 | 0 |
| IRS990/InvestmentsOtherSecuritiesGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentsProgramRelatedGrp/BOYAmt | 0 | 0 |
| IRS990/InvestmentsProgramRelatedGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentsPubTradedSecGrp/BOYAmt | 0 | 0 |
| IRS990/InvestmentsPubTradedSecGrp/EOYAmt | 0 | 0 |
| IRS990/IRPDocumentCnt | 0 | 0 |
| IRS990/IRPDocumentW2GCnt | 0 | 0 |
| IRS990/LandBldgEquipAccumDeprecAmt | 0 | 50912089 |
| IRS990/LandBldgEquipBasisNetGrp/BOYAmt | 0 | 80965979 |
| IRS990/LandBldgEquipBasisNetGrp/EOYAmt | 0 | 82449771 |
| IRS990/LandBldgEquipCostOrOtherBssAmt | 0 | 133361860 |
| IRS990/LegalDomicileStateCd | 0 | NY |
| IRS990/LoanOutstandingInd | 0 | false |
| IRS990/LoansFromOfficersDirectorsGrp/BOYAmt | 0 | 0 |
| IRS990/LoansFromOfficersDirectorsGrp/EOYAmt | 0 | 0 |
| IRS990/LobbyingActivitiesInd | 0 | false |
| IRS990/LocalChaptersInd | 0 | false |
| IRS990/MaterialDiversionOrMisuseInd | 0 | false |
| IRS990/MembersOrStockholdersInd | 0 | true |
| IRS990/MethodOfAccountingAccrualInd | 0 | X |
| IRS990/MinutesOfCommitteesInd | 0 | true |
| IRS990/MinutesOfGoverningBodyInd | 0 | true |
| IRS990/MissionDesc | 0 | SUPPORT ITS MEMBER CORPORATIONS BY ACQUIRING, OWNING, FINANCING, OPERATING AND DISPOSING OF REAL ESTATE PRIMARILY FOR USE AS STAFF HOUSING FOR ITS MEMBERS. |
| IRS990/MoreThan5000KToIndividualsInd | 0 | false |
| IRS990/MoreThan5000KToOrgInd | 0 | false |
| IRS990/MortgNotesPyblScrdInvstPropGrp/BOYAmt | 0 | 145349269 |
| IRS990/MortgNotesPyblScrdInvstPropGrp/EOYAmt | 0 | 145349269 |
| IRS990/NetAssetsOrFundBalancesBOYAmt | 0 | -44835383 |
| IRS990/NetAssetsOrFundBalancesEOYAmt | 0 | -42381858 |
| IRS990/NetGainOrLossInvestmentsGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/NetIncmFromFundraisingEvtGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/NetIncomeFromGamingGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/NetIncomeOrLossGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/NetRentalIncomeOrLossGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/NondeductibleContributionsInd | 0 | false |
| IRS990/OccupancyGrp/ProgramServicesAmt | 0 | 4580566 |
| IRS990/OccupancyGrp/TotalAmt | 0 | 4580566 |
| IRS990/OfficeExpensesGrp/ProgramServicesAmt | 0 | 295746 |
| IRS990/OfficeExpensesGrp/TotalAmt | 0 | 295746 |
| IRS990/OfficerMailingAddressInd | 0 | false |
| IRS990/OperateHospitalInd | 0 | false |
| IRS990/Organization501c3Ind | 0 | X |
| IRS990/OrgDoesNotFollowSFAS117Ind | 0 | X |
| IRS990/OtherAssetsTotalGrp/BOYAmt | 0 | 2047214 |
| IRS990/OtherAssetsTotalGrp/EOYAmt | 0 | 2159151 |
| IRS990/OtherEmployeeBenefitsGrp/TotalAmt | 0 | 0 |
| IRS990/OtherExpensesGrp/Desc | 0 | PURCHASED SERVICE SALARIES |
| IRS990/OtherExpensesGrp/Desc | 1 | PURCHASED SERVICE BENEFITS |
| IRS990/OtherExpensesGrp/Desc | 2 | REPAIR & MAINTENANCE |
| IRS990/OtherExpensesGrp/Desc | 3 | CLEANING |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 0 | 3670394 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 1 | 1322707 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 2 | 3247982 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 3 | 396825 |
| IRS990/OtherExpensesGrp/TotalAmt | 0 | 3670394 |
| IRS990/OtherExpensesGrp/TotalAmt | 1 | 1322707 |
| IRS990/OtherExpensesGrp/TotalAmt | 2 | 3247982 |
| IRS990/OtherExpensesGrp/TotalAmt | 3 | 396825 |
| IRS990/OtherLiabilitiesGrp/BOYAmt | 0 | 2220380 |
| IRS990/OtherLiabilitiesGrp/EOYAmt | 0 | 2177185 |
| IRS990/OtherOrganizationDsc | 0 | LLC |
| IRS990/OtherRevenueMiscGrp/BusinessCd | 0 | 812300 |
| IRS990/OtherRevenueMiscGrp/BusinessCd | 1 | 812930 |
| IRS990/OtherRevenueMiscGrp/Desc | 0 | LAUNDRY INCOME |
| IRS990/OtherRevenueMiscGrp/Desc | 1 | GARAGE INCOME |
| IRS990/OtherRevenueMiscGrp/RelatedOrExemptFuncIncomeAmt | 0 | 168300 |
| IRS990/OtherRevenueMiscGrp/RelatedOrExemptFuncIncomeAmt | 1 | 205076 |
| IRS990/OtherRevenueMiscGrp/TotalRevenueColumnAmt | 0 | 168300 |
| IRS990/OtherRevenueMiscGrp/TotalRevenueColumnAmt | 1 | 205076 |
| IRS990/OtherRevenueTotalAmt | 0 | 373376 |
| IRS990/OtherSalariesAndWagesGrp/TotalAmt | 0 | 0 |
| IRS990/OthNotesLoansReceivableNetGrp/BOYAmt | 0 | 0 |
| IRS990/OthNotesLoansReceivableNetGrp/EOYAmt | 0 | 0 |
| IRS990/PartialLiquidationInd | 0 | false |
| IRS990/PaymentsToAffiliatesGrp/TotalAmt | 0 | 0 |
| IRS990/PayPremiumsPrsnlBnftCntrctInd | 0 | false |
| IRS990/PayrollTaxesGrp/TotalAmt | 0 | 0 |
| IRS990/PdInCapSrplsLandBldgEqpFundGrp/BOYAmt | 0 | 0 |
| IRS990/PdInCapSrplsLandBldgEqpFundGrp/EOYAmt | 0 | 0 |
| IRS990/PensionPlanContributionsGrp/TotalAmt | 0 | 0 |
| IRS990/PledgesAndGrantsReceivableGrp/BOYAmt | 0 | 0 |
| IRS990/PledgesAndGrantsReceivableGrp/EOYAmt | 0 | 0 |
| IRS990/PoliticalCampaignActyInd | 0 | false |
| IRS990/PrepaidExpensesDefrdChargesGrp/BOYAmt | 0 | 2276490 |
| IRS990/PrepaidExpensesDefrdChargesGrp/EOYAmt | 0 | 2043672 |
| IRS990/PrincipalOfficerNm | 0 | DONALD SCANLON |
| IRS990/ProfessionalFundraisingInd | 0 | false |
| IRS990/ProgramServiceRevenueGrp/BusinessCd | 0 | 531110 |
| IRS990/ProgramServiceRevenueGrp/Desc | 0 | RENTAL INCOME |
| IRS990/ProgramServiceRevenueGrp/RelatedOrExemptFuncIncomeAmt | 0 | 27795867 |
| IRS990/ProgramServiceRevenueGrp/TotalRevenueColumnAmt | 0 | 27795867 |
| IRS990/ProhibitedTaxShelterTransInd | 0 | false |
| IRS990/PYBenefitsPaidToMembersAmt | 0 | 0 |
| IRS990/PYContributionsGrantsAmt | 0 | 0 |
| IRS990/PYExcessBenefitTransInd | 0 | false |
| IRS990/PYGrantsAndSimilarPaidAmt | 0 | 1594198 |
| IRS990/PYInvestmentIncomeAmt | 0 | 125606 |
| IRS990/PymtTravelEntrtnmntPubOfclGrp/TotalAmt | 0 | 0 |
| IRS990/PYOtherExpensesAmt | 0 | 24451742 |
| IRS990/PYOtherRevenueAmt | 0 | 369498 |
| IRS990/PYProgramServiceRevenueAmt | 0 | 28321069 |
| IRS990/PYRevenuesLessExpensesAmt | 0 | 2770233 |
| IRS990/PYSalariesCompEmpBnftPaidAmt | 0 | 0 |
| IRS990/PYTotalExpensesAmt | 0 | 26045940 |
| IRS990/PYTotalProfFndrsngExpnsAmt | 0 | 0 |
| IRS990/PYTotalRevenueAmt | 0 | 28816173 |
| IRS990/QuidProQuoContributionsInd | 0 | false |
| IRS990/RcvblFromDisqualifiedPrsnGrp/BOYAmt | 0 | 0 |
| IRS990/RcvblFromDisqualifiedPrsnGrp/EOYAmt | 0 | 0 |
| IRS990/RcvFndsToPayPrsnlBnftCntrctInd | 0 | false |
| IRS990/ReceivablesFromOfficersEtcGrp/BOYAmt | 0 | 0 |
| IRS990/ReceivablesFromOfficersEtcGrp/EOYAmt | 0 | 0 |
| IRS990/ReconcilationRevenueExpnssAmt | 0 | 2453525 |
| IRS990/RegularMonitoringEnfrcInd | 0 | true |
| IRS990/RelatedEntityInd | 0 | true |
| IRS990/RelatedOrganizationCtrlEntInd | 0 | true |
| IRS990/RentalIncomeOrLossGrp/PersonalAmt | 0 | 0 |
| IRS990/RentalIncomeOrLossGrp/RealAmt | 0 | 0 |
| IRS990/ReportInvestmentsOtherSecInd | 0 | false |
| IRS990/ReportLandBuildingEquipmentInd | 0 | true |
| IRS990/ReportOtherAssetsInd | 0 | false |
| IRS990/ReportOtherLiabilitiesInd | 0 | true |
| IRS990/ReportProgramRelatedInvstInd | 0 | false |
| IRS990/RevenueAmt | 0 | 28169243 |
| IRS990/RoyaltiesGrp/TotalAmt | 0 | 0 |
| IRS990/RoyaltiesRevenueGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/RtnEarnEndowmentIncmOthFndsGrp/BOYAmt | 0 | -44835383 |
| IRS990/RtnEarnEndowmentIncmOthFndsGrp/EOYAmt | 0 | -42381858 |
| IRS990/SavingsAndTempCashInvstGrp/BOYAmt | 0 | 14698434 |
| IRS990/SavingsAndTempCashInvstGrp/EOYAmt | 0 | 14187889 |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/Contribution35ControlledInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/ContributionControllerInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/ContributionFamilyInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/ControlledDisqualifiedPrsnInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/DisqualifiedPrsnControllIntInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/DisqualifiedPrsnOwnrIntInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/ExcessBusinessHoldingsRulesInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/ListedByNameGoverningDocInd | 0 | true |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/LoanDisqualifiedPersonInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/OrganizationChangeSuprtOrgInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/PaymentSubstantialContribtrInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/SupportedOrgNotOrganizedUSInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/SupportedOrgSectionC456Ind | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/SupportNonSupportedOrgInd | 0 | false |
| IRS990ScheduleA/Form990SchASupportingOrgGrp/SuprtOrgNoIRSDeterminationInd | 0 | false |
| IRS990ScheduleA/Form990SchAType1SuprtOrgGrp/OperateBenefitNonSuprtOrgInd | 0 | false |
| IRS990ScheduleA/Form990SchAType1SuprtOrgGrp/PowerAppointMajorityDirTrstInd | 0 | true |
| IRS990ScheduleA/SupportedOrganizationsCnt | 0 | 3 |
| IRS990ScheduleA/SupportedOrganizationsTotalCnt | 0 | 3 |
| IRS990ScheduleA/SupportedOrgInformationGrp/EIN | 0 | 136171197 |
| IRS990ScheduleA/SupportedOrgInformationGrp/EIN | 1 | 131624096 |
| IRS990ScheduleA/SupportedOrgInformationGrp/EIN | 2 | 133852596 |
| IRS990ScheduleA/SupportedOrgInformationGrp/GoverningDocumentListedInd | 0 | true |
| IRS990ScheduleA/SupportedOrgInformationGrp/GoverningDocumentListedInd | 1 | true |
| IRS990ScheduleA/SupportedOrgInformationGrp/GoverningDocumentListedInd | 2 | true |
| IRS990ScheduleA/SupportedOrgInformationGrp/OrganizationTypeCd | 0 | 2 |
| IRS990ScheduleA/SupportedOrgInformationGrp/OrganizationTypeCd | 1 | 3 |
| IRS990ScheduleA/SupportedOrgInformationGrp/OrganizationTypeCd | 2 | 9 |
| IRS990ScheduleA/SupportedOrgInformationGrp/OtherSupportAmt | 0 | 0 |
| IRS990ScheduleA/SupportedOrgInformationGrp/OtherSupportAmt | 1 | 0 |
| IRS990ScheduleA/SupportedOrgInformationGrp/OtherSupportAmt | 2 | 0 |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportAmt | 0 | 175996 |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportAmt | 1 | 262284 |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportAmt | 2 | 201057 |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportedOrganizationName/BusinessNameLine1Txt | 0 | ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportedOrganizationName/BusinessNameLine1Txt | 1 | MOUNT SINAI HOSPITAL |
| IRS990ScheduleA/SupportedOrgInformationGrp/SupportedOrganizationName/BusinessNameLine1Txt | 2 | MSMC REALTY CORPORATION |
| IRS990ScheduleA/SupportingOrganization509a3Ind | 0 | X |
| IRS990ScheduleA/SupportingOrgType1Ind | 0 | X |
| IRS990ScheduleA/SupportSumAmt | 0 | 639337 |
| IRS990/ScheduleBRequiredInd | 0 | false |
| IRS990ScheduleD/BuildingsGrp/BookValueAmt | 0 | 47916672 |
| IRS990ScheduleD/BuildingsGrp/DepreciationAmt | 0 | 38460529 |
| IRS990ScheduleD/BuildingsGrp/OtherCostOrOtherBasisAmt | 0 | 86377201 |
| IRS990ScheduleD/EquipmentGrp/BookValueAmt | 0 | 23790349 |
| IRS990ScheduleD/EquipmentGrp/DepreciationAmt | 0 | 7258213 |
| IRS990ScheduleD/EquipmentGrp/OtherCostOrOtherBasisAmt | 0 | 31048562 |
| IRS990ScheduleD/ExpensesNotRptFinclStmtAmt | 0 | 639337 |
| IRS990ScheduleD/ExpensesSubtotalAmt | 0 | 25183399 |
| IRS990ScheduleD/FederalIncomeTaxLiabilityAmt | 0 | 0 |
| IRS990ScheduleD/LandGrp/BookValueAmt | 0 | 1912500 |
| IRS990ScheduleD/LandGrp/OtherCostOrOtherBasisAmt | 0 | 1912500 |
| IRS990ScheduleD/OtherExpensesNotIncludedAmt | 0 | 639337 |
| IRS990ScheduleD/OtherLandBuildingsGrp/BookValueAmt | 0 | 8830250 |
| IRS990ScheduleD/OtherLandBuildingsGrp/DepreciationAmt | 0 | 5193347 |
| IRS990ScheduleD/OtherLandBuildingsGrp/OtherCostOrOtherBasisAmt | 0 | 14023597 |
| IRS990ScheduleD/OtherLiabilitiesOrgGrp/Amt | 0 | 2159151 |
| IRS990ScheduleD/OtherLiabilitiesOrgGrp/Amt | 1 | 18034 |
| IRS990ScheduleD/OtherLiabilitiesOrgGrp/Desc | 0 | TENANT SECURITY DEPOSITS |
| IRS990ScheduleD/OtherLiabilitiesOrgGrp/Desc | 1 | DUE TO RELATED ORGANIZATIONS |
| IRS990ScheduleD/RevenueSubtotalAmt | 0 | 28276261 |
| IRS990ScheduleD/SupplementalInformationDetail/ExplanationTxt | 0 | MSMC RESIDENTIAL REALTY MADE THE FOLLOWING TRANSFERS TO SUPPORTING ORGANIZATIONS: $262,284 TO MOUNT SINAI HOSPITAL, $175,996 TO ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI AND $201,057 TO MSMC REALTY CORPORATION: THE TOTAL OF THE THREE TRANSFERS EQUALS $639,337. |
| IRS990ScheduleD/SupplementalInformationDetail/FormAndLineReferenceDesc | 0 | SCHEDULE D, Part XII, LINE 4B |
| IRS990ScheduleD/TotalBookValueLandBuildingsAmt | 0 | 82449771 |
| IRS990ScheduleD/TotalExpensesPerForm990Amt | 0 | 25822736 |
| IRS990ScheduleD/TotalLiabilityAmt | 0 | 2177185 |
| IRS990ScheduleD/TotalRevenuePerForm990Amt | 0 | 28276261 |
| IRS990ScheduleD/TotalRevEtcAuditedFinclStmtAmt | 0 | 28276261 |
| IRS990ScheduleD/TotExpnsEtcAuditedFinclStmtAmt | 0 | 25183399 |
| IRS990ScheduleI/GrantRecordsMaintainedInd | 0 | true |
| IRS990ScheduleI/RecipientTable/CashGrantAmt | 0 | 262284 |
| IRS990ScheduleI/RecipientTable/CashGrantAmt | 1 | 175996 |
| IRS990ScheduleI/RecipientTable/CashGrantAmt | 2 | 201057 |
| IRS990ScheduleI/RecipientTable/IRCSectionDesc | 0 | 501(C)(3) |
| IRS990ScheduleI/RecipientTable/IRCSectionDesc | 1 | 501(C)(3) |
| IRS990ScheduleI/RecipientTable/IRCSectionDesc | 2 | 501(C)(3) |
| IRS990ScheduleI/RecipientTable/PurposeOfGrantTxt | 0 | distribution |
| IRS990ScheduleI/RecipientTable/PurposeOfGrantTxt | 1 | distribution |
| IRS990ScheduleI/RecipientTable/PurposeOfGrantTxt | 2 | distribution |
| IRS990ScheduleI/RecipientTable/RecipientBusinessName/BusinessNameLine1Txt | 0 | The Mount Sinai Hospital |
| IRS990ScheduleI/RecipientTable/RecipientBusinessName/BusinessNameLine1Txt | 1 | Icahn School of Medicine at Mount Sinai |
| IRS990ScheduleI/RecipientTable/RecipientBusinessName/BusinessNameLine1Txt | 2 | MSMC Realty Corporation |
| IRS990ScheduleI/RecipientTable/RecipientEIN | 0 | 131624096 |
| IRS990ScheduleI/RecipientTable/RecipientEIN | 1 | 136171197 |
| IRS990ScheduleI/RecipientTable/RecipientEIN | 2 | 133852596 |
| IRS990ScheduleI/RecipientTable/USAddress/AddressLine1Txt | 0 | One Gustave L Levy Place |
| IRS990ScheduleI/RecipientTable/USAddress/AddressLine1Txt | 1 | One Gustave L Levy Place |
| IRS990ScheduleI/RecipientTable/USAddress/AddressLine1Txt | 2 | One Gustave L Levy Place |
| IRS990ScheduleI/RecipientTable/USAddress/CityNm | 0 | New York |
| IRS990ScheduleI/RecipientTable/USAddress/CityNm | 1 | New York |
| IRS990ScheduleI/RecipientTable/USAddress/CityNm | 2 | New York |
| IRS990ScheduleI/RecipientTable/USAddress/StateAbbreviationCd | 0 | NY |
| IRS990ScheduleI/RecipientTable/USAddress/StateAbbreviationCd | 1 | NY |
| IRS990ScheduleI/RecipientTable/USAddress/StateAbbreviationCd | 2 | NY |
| IRS990ScheduleI/RecipientTable/USAddress/ZIPCd | 0 | 10029 |
| IRS990ScheduleI/RecipientTable/USAddress/ZIPCd | 1 | 10029 |
| IRS990ScheduleI/RecipientTable/USAddress/ZIPCd | 2 | 10029 |
| IRS990ScheduleI/SupplementalInformationDetail/ExplanationTxt | 0 | The transfer of funds to tax exempt members was a distribution. The members will use the funds to further their exempt function. We do not monitor the use of our grant funds because all grants are made to related tax-exempt entities and are used to further their exempt purposes. |
| IRS990ScheduleI/SupplementalInformationDetail/FormAndLineReferenceDesc | 0 | Part I, Question 2 |
| IRS990ScheduleI/Total501c3OrgCnt | 0 | 3 |
| IRS990ScheduleJ/AnyNonFixedPaymentsInd | 0 | false |
| IRS990ScheduleJ/CompBasedOnRevenueOfFlngOrgInd | 0 | false |
| IRS990ScheduleJ/CompBsdNetEarnsFlngOrgInd | 0 | false |
| IRS990ScheduleJ/CompBsdNetEarnsRltdOrgsInd | 0 | false |
| IRS990ScheduleJ/CompBsdOnRevRelatedOrgsInd | 0 | false |
| IRS990ScheduleJ/EquityBasedCompArrngmInd | 0 | false |
| IRS990ScheduleJ/InitialContractExceptionInd | 0 | false |
| IRS990/ScheduleJRequiredInd | 0 | true |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/BaseCompensationFilingOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/BonusFilingOrganizationAmount | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/BonusRelatedOrganizationsAmt | 0 | 339000 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/CompensationBasedOnRltdOrgsAmt | 0 | 1030000 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/CompReportPrior990FilingOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/CompReportPrior990RltdOrgsAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/DeferredCompensationFlngOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/DeferredCompRltdOrgsAmt | 0 | 26500 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/NontaxableBenefitsFilingOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/NontaxableBenefitsRltdOrgsAmt | 0 | 31464 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/OtherCompensationFilingOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/OtherCompensationRltdOrgsAmt | 0 | 352029 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/PersonNm | 0 | DONALD T SCANLON 1 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/TitleTxt | 0 | PRESIDENT AND TRUSTEE |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/TotalCompensationFilingOrgAmt | 0 | 0 |
| IRS990ScheduleJ/RltdOrgOfficerTrstKeyEmplGrp/TotalCompensationRltdOrgsAmt | 0 | 1778993 |
| IRS990ScheduleJ/SeverancePaymentInd | 0 | false |
| IRS990ScheduleJ/SupplementalInformationDetail/ExplanationTxt | 0 | COMPENSATION FOOTNOTES (1) Compensation and benefits are funded from The Mount Sinai Hospital, Icahn School of Medicine at Mount Sinai, Beth Israel Medical Center, St. Luke's-Roosevelt Hospital Center and/or New York Eye and Ear Infirmary. |
| IRS990ScheduleJ/SupplementalInformationDetail/FormAndLineReferenceDesc | 0 | PART VII, SECTION A & SCHEDULE J |
| IRS990ScheduleJ/SupplementalNonqualRtrPlanInd | 0 | false |