| IRS990/AccountantCompileOrReviewInd | 0 | false |
| IRS990/AccountsPayableAccrExpnssGrp/BOYAmt | 0 | 112127 |
| IRS990/AccountsPayableAccrExpnssGrp/EOYAmt | 0 | 111010 |
| IRS990/AccountsReceivableGrp/EOYAmt | 0 | 0 |
| IRS990/ActivitiesConductedPrtshpInd | 0 | false |
| IRS990/ActivityOrMissionDesc | 0 | Muir Heritage Land Trust protects and cares for open space, ranches, farms, parkland, and shoreline in Contra Costa County. |
| IRS990/AdvertisingGrp/TotalAmt | 0 | 0 |
| IRS990/AllOtherContributionsAmt | 0 | 6149860 |
| IRS990/AllOtherExpensesGrp/FundraisingAmt | 0 | 62447 |
| IRS990/AllOtherExpensesGrp/ManagementAndGeneralAmt | 0 | 15948 |
| IRS990/AllOtherExpensesGrp/ProgramServicesAmt | 0 | 27760 |
| IRS990/AllOtherExpensesGrp/TotalAmt | 0 | 106155 |
| IRS990/AmendedReturnInd | 0 | X |
| IRS990/AnnualDisclosureCoveredPrsnInd | 0 | true |
| IRS990/AuditCommitteeInd | 0 | true |
| IRS990/BackupWthldComplianceInd | 0 | true |
| IRS990/BenefitsToMembersGrp/TotalAmt | 0 | 0 |
| IRS990/BooksInCareOfDetail/PersonNm | 0 | Neil Roscoe |
| IRS990/BooksInCareOfDetail/PhoneNum | 0 | 9252285460 |
| IRS990/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | PO Box 31 |
| IRS990/BooksInCareOfDetail/USAddress/CityNm | 0 | Martinez |
| IRS990/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | CA |
| IRS990/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 94553 |
| IRS990/BusinessRlnWith35CtrlEntInd | 0 | false |
| IRS990/BusinessRlnWithFamMemInd | 0 | false |
| IRS990/BusinessRlnWithOrgMemInd | 0 | false |
| IRS990/CashNonInterestBearingGrp/BOYAmt | 0 | 1304914 |
| IRS990/CashNonInterestBearingGrp/EOYAmt | 0 | 1522545 |
| IRS990/ChangeToOrgDocumentsInd | 0 | false |
| IRS990/CntrctRcvdGreaterThan100KCnt | 0 | 0 |
| IRS990/CollectionsOfArtInd | 0 | false |
| IRS990/CompCurrentOfcrDirectorsGrp/FundraisingAmt | 0 | 12817 |
| IRS990/CompCurrentOfcrDirectorsGrp/ManagementAndGeneralAmt | 0 | 88820 |
| IRS990/CompCurrentOfcrDirectorsGrp/ProgramServicesAmt | 0 | 154706 |
| IRS990/CompCurrentOfcrDirectorsGrp/TotalAmt | 0 | 256343 |
| IRS990/CompDisqualPersonsGrp/TotalAmt | 0 | 0 |
| IRS990/CompensationFromOtherSrcsInd | 0 | false |
| IRS990/CompensationProcessCEOInd | 0 | true |
| IRS990/CompensationProcessOtherInd | 0 | true |
| IRS990/ConferencesMeetingsGrp/FundraisingAmt | 0 | 250 |
| IRS990/ConferencesMeetingsGrp/ManagementAndGeneralAmt | 0 | 924 |
| IRS990/ConferencesMeetingsGrp/TotalAmt | 0 | 1174 |
| IRS990/ConflictOfInterestPolicyInd | 0 | true |
| IRS990/ConservationEasementsInd | 0 | true |
| IRS990/ConsolidatedAuditFinclStmtInd | 0 | false |
| IRS990/CreditCounselingInd | 0 | false |
| IRS990/CYBenefitsPaidToMembersAmt | 0 | 0 |
| IRS990/CYContributionsGrantsAmt | 0 | 6270060 |
| IRS990/CYGrantsAndSimilarPaidAmt | 0 | 10250 |
| IRS990/CYInvestmentIncomeAmt | 0 | 1103 |
| IRS990/CYOtherExpensesAmt | 0 | 4991357 |
| IRS990/CYOtherRevenueAmt | 0 | 204683 |
| IRS990/CYProgramServiceRevenueAmt | 0 | 48580 |
| IRS990/CYRevenuesLessExpensesAmt | 0 | 454062 |
| IRS990/CYSalariesCompEmpBnftPaidAmt | 0 | 1068757 |
| IRS990/CYTotalExpensesAmt | 0 | 6070364 |
| IRS990/CYTotalFundraisingExpenseAmt | 0 | 431053 |
| IRS990/CYTotalProfFndrsngExpnsAmt | 0 | 0 |
| IRS990/CYTotalRevenueAmt | 0 | 6524426 |
| IRS990/DecisionsSubjectToApprovaInd | 0 | false |
| IRS990/DeductibleArtContributionInd | 0 | false |
| IRS990/DeductibleNonCashContriInd | 0 | true |
| IRS990/DelegationOfMgmtDutiesInd | 0 | false |
| IRS990/DepreciationDepletionGrp/FundraisingAmt | 0 | 9975 |
| IRS990/DepreciationDepletionGrp/ManagementAndGeneralAmt | 0 | 7888 |
| IRS990/DepreciationDepletionGrp/ProgramServicesAmt | 0 | 32422 |
| IRS990/DepreciationDepletionGrp/TotalAmt | 0 | 50285 |
| IRS990/Desc | 0 | Conservation Activities:During the year ended June 30, 2021, funds were expended in order to carry out the goals of the John Muir Land Trust Program: to protect, restore, and enhance each property's natural ecosystem and resource values, and preserve, in perpetuity, each property's open space values, scenic beauty and diverse habitats.For a complete discussion of the Land Trust's accomplishments, please visit the organization's website where additional information is available:www.jmlt.org |
| IRS990/DescribedInSection501c3Ind | 0 | true |
| IRS990/DisregardedEntityInd | 0 | false |
| IRS990/DocumentRetentionPolicyInd | 0 | true |
| IRS990/DonorAdvisedFundInd | 0 | false |
| IRS990/DonorRestrictionNetAssetsGrp/BOYAmt | 0 | 1053588 |
| IRS990/DonorRestrictionNetAssetsGrp/EOYAmt | 0 | 1639627 |
| IRS990/DonorRstrOrQuasiEndowmentsInd | 0 | true |
| IRS990/ElectionOfBoardMembersInd | 0 | false |
| IRS990/EmployeeCnt | 0 | 20 |
| IRS990/EmploymentTaxReturnsFiledInd | 0 | true |
| IRS990/EngagedInExcessBenefitTransInd | 0 | false |
| IRS990/ExpenseAmt | 0 | 4711760 |
| IRS990/FamilyOrBusinessRlnInd | 0 | false |
| IRS990/FederalGrantAuditRequiredInd | 0 | false |
| IRS990/FeesForServicesAccountingGrp/ManagementAndGeneralAmt | 0 | 13358 |
| IRS990/FeesForServicesAccountingGrp/TotalAmt | 0 | 13358 |
| IRS990/FeesForServicesLegalGrp/TotalAmt | 0 | 0 |
| IRS990/FeesForServicesLobbyingGrp/TotalAmt | 0 | 0 |
| IRS990/FeesForServicesManagementGrp/TotalAmt | 0 | 0 |
| IRS990/FeesForServicesOtherGrp/FundraisingAmt | 0 | 14293 |
| IRS990/FeesForServicesOtherGrp/ProgramServicesAmt | 0 | 5314 |
| IRS990/FeesForServicesOtherGrp/TotalAmt | 0 | 19607 |
| 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/Form1098CFiledInd | 0 | false |
| IRS990/Form8282FiledCnt | 0 | 0 |
| IRS990/Form8282PropertyDisposedOfInd | 0 | false |
| IRS990/Form8899Filedind | 0 | false |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 0 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 1 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 2 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 3 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 4 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 5 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 6 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 7 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 8 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 9 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 10 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 11 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 12 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 13 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 14 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 15 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRltdOrgRt | 16 | 0.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 0 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 1 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 2 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 3 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 4 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 5 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 6 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 7 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 8 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 9 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 10 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 11 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 12 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 13 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 14 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 15 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 16 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 0 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 1 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 2 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 3 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 4 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 5 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 6 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 7 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 8 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 9 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 10 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 11 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 12 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 13 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 0 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 1 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 2 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 3 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 4 | X |
| IRS990/Form990PartVIISectionAGrp/OfficerInd | 5 | X |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 0 | 19987 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 1 | 12060 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 2 | 32671 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 3 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 4 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 5 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 6 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 7 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 8 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 9 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 10 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 11 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 12 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 13 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 14 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 15 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 16 | 0 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 0 | Linus Eukel |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 1 | Krista Jordan |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 2 | Neil Roscoe |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 3 | Katie Hill |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 4 | Arthur Bart-Williams |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 5 | Stephanie Becker |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 6 | Bill Wadsworth |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 7 | Eliot Hudson |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 8 | Dawn Block |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 9 | Charles Lewis |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 10 | Jan Berckefeldt |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 11 | Jack Cortis |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 12 | Steve Kirby |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 13 | Tim Lipman |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 14 | Eileen McCauley |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 15 | Ted Radosevich |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 16 | Karen Sakata |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 0 | 151754 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 1 | 102617 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 2 | 81065 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 3 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 4 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 5 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 6 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 7 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 8 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 9 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 10 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 11 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 12 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 13 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 14 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 15 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 16 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 0 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 1 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 2 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 3 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 4 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 5 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 6 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 7 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 8 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 9 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 10 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 11 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 12 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 13 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 14 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 15 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 16 | 0 |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 0 | Exec. Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 1 | Dir of Philanthrop |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 2 | CFO |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 3 | Chair |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 4 | Vice Chair |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 5 | Secretary |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 6 | Treasurer |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 7 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 8 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 9 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 10 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 11 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 12 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 13 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 14 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 15 | Director |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 16 | Director |
| IRS990/Form990ProvidedToGvrnBodyInd | 0 | true |
| IRS990/FormationYr | 0 | 1989 |
| IRS990/FormerOfcrEmployeesListedInd | 0 | false |
| IRS990/FSAuditedBasisGrp/SeparateBasisFinclStmtInd | 0 | X |
| IRS990/FSAuditedInd | 0 | true |
| IRS990/FundraisingActivitiesInd | 0 | false |
| IRS990/GamingActivitiesInd | 0 | false |
| IRS990/GoverningBodyVotingMembersCnt | 0 | 14 |
| IRS990/GovernmentGrantsAmt | 0 | 120200 |
| IRS990/GrantsToDomesticIndividualsGrp/TotalAmt | 0 | 0 |
| IRS990/GrantsToDomesticOrgsGrp/ProgramServicesAmt | 0 | 10250 |
| IRS990/GrantsToDomesticOrgsGrp/TotalAmt | 0 | 10250 |
| IRS990/GrantsToIndividualsInd | 0 | false |
| IRS990/GrantsToOrganizationsInd | 0 | false |
| IRS990/GrantToRelatedPersonInd | 0 | false |
| IRS990/GrossReceiptsAmt | 0 | 6524426 |
| IRS990/GroupReturnForAffiliatesInd | 0 | false |
| IRS990/IncludeFIN48FootnoteInd | 0 | true |
| IRS990/IncmFromInvestBondProceedsGrp/TotalRevenueColumnAmt | 0 | 0 |
| IRS990/IndependentAuditFinclStmtInd | 0 | true |
| IRS990/IndependentVotingMemberCnt | 0 | 14 |
| IRS990/IndivRcvdGreaterThan100KCnt | 0 | 2 |
| IRS990/IndoorTanningServicesInd | 0 | false |
| IRS990/InfoInScheduleOPartVIInd | 0 | X |
| IRS990/InfoInScheduleOPartXIInd | 0 | X |
| IRS990/InformationTechnologyGrp/FundraisingAmt | 0 | 20393 |
| IRS990/InformationTechnologyGrp/ManagementAndGeneralAmt | 0 | 16128 |
| IRS990/InformationTechnologyGrp/ProgramServicesAmt | 0 | 66288 |
| IRS990/InformationTechnologyGrp/TotalAmt | 0 | 102809 |
| IRS990/InsuranceGrp/FundraisingAmt | 0 | 3642 |
| IRS990/InsuranceGrp/ManagementAndGeneralAmt | 0 | 2880 |
| IRS990/InsuranceGrp/ProgramServicesAmt | 0 | 11839 |
| IRS990/InsuranceGrp/TotalAmt | 0 | 18361 |
| IRS990/IntangibleAssetsGrp/EOYAmt | 0 | 0 |
| IRS990/InterestGrp/TotalAmt | 0 | 0 |
| IRS990/InventoriesForSaleOrUseGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentIncomeGrp/ExclusionAmt | 0 | 1103 |
| IRS990/InvestmentIncomeGrp/TotalRevenueColumnAmt | 0 | 1103 |
| IRS990/InvestmentInJointVentureInd | 0 | false |
| IRS990/InvestmentsOtherSecuritiesGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentsProgramRelatedGrp/EOYAmt | 0 | 0 |
| IRS990/InvestmentsPubTradedSecGrp/EOYAmt | 0 | 0 |
| IRS990/IRPDocumentCnt | 0 | 3 |
| IRS990/IRPDocumentW2GCnt | 0 | 0 |
| IRS990/LandBldgEquipAccumDeprecAmt | 0 | 196944 |
| IRS990/LandBldgEquipBasisNetGrp/BOYAmt | 0 | 388857 |
| IRS990/LandBldgEquipBasisNetGrp/EOYAmt | 0 | 561536 |
| IRS990/LandBldgEquipCostOrOtherBssAmt | 0 | 758480 |
| IRS990/LegalDomicileStateCd | 0 | CA |
| IRS990/LoanOutstandingInd | 0 | false |
| IRS990/LobbyingActivitiesInd | 0 | false |
| IRS990/LocalChaptersInd | 0 | false |
| IRS990/MaterialDiversionOrMisuseInd | 0 | false |
| IRS990/MembersOrStockholdersInd | 0 | false |
| IRS990/MethodOfAccountingAccrualInd | 0 | X |
| IRS990/MinutesOfCommitteesInd | 0 | true |
| IRS990/MinutesOfGoverningBodyInd | 0 | true |
| IRS990/MissionDesc | 0 | The vitality of open spaces is essential to the health of our earth, air, water, native plants, and animals. Our goal is to ensure that the beauty, diversity, and fullness of our wild lands continue to enrich and sustain all generations of life. |
| IRS990/MoreThan5000KToIndividualsInd | 0 | false |
| IRS990/MoreThan5000KToOrgInd | 0 | false |
| IRS990/NetAssetsOrFundBalancesBOYAmt | 0 | 18499741 |
| IRS990/NetAssetsOrFundBalancesEOYAmt | 0 | 23113803 |
| 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/NoDonorRestrictionNetAssetsGrp/BOYAmt | 0 | 17446153 |
| IRS990/NoDonorRestrictionNetAssetsGrp/EOYAmt | 0 | 21474176 |
| IRS990/NoncashContributionsAmt | 0 | 4224585 |
| IRS990/NondeductibleContributionsInd | 0 | true |
| IRS990/NondeductibleContriDisclInd | 0 | true |
| IRS990/OccupancyGrp/FundraisingAmt | 0 | 7706 |
| IRS990/OccupancyGrp/ManagementAndGeneralAmt | 0 | 6094 |
| IRS990/OccupancyGrp/ProgramServicesAmt | 0 | 25047 |
| IRS990/OccupancyGrp/TotalAmt | 0 | 38847 |
| IRS990/OfficeExpensesGrp/FundraisingAmt | 0 | 2718 |
| IRS990/OfficeExpensesGrp/ManagementAndGeneralAmt | 0 | 1897 |
| IRS990/OfficeExpensesGrp/ProgramServicesAmt | 0 | 7961 |
| IRS990/OfficeExpensesGrp/TotalAmt | 0 | 12576 |
| IRS990/OfficerMailingAddressInd | 0 | false |
| IRS990/OperateHospitalInd | 0 | false |
| IRS990/Organization501c3Ind | 0 | X |
| IRS990/OrganizationFollowsFASB117Ind | 0 | X |
| IRS990/OtherAssetsTotalGrp/BOYAmt | 0 | 16526406 |
| IRS990/OtherAssetsTotalGrp/EOYAmt | 0 | 20648844 |
| IRS990/OtherChangesInNetAssetsAmt | 0 | 4160000 |
| IRS990/OtherEmployeeBenefitsGrp/FundraisingAmt | 0 | 19473 |
| IRS990/OtherEmployeeBenefitsGrp/ManagementAndGeneralAmt | 0 | 15400 |
| IRS990/OtherEmployeeBenefitsGrp/ProgramServicesAmt | 0 | 63296 |
| IRS990/OtherEmployeeBenefitsGrp/TotalAmt | 0 | 98169 |
| IRS990/OtherExpensesGrp/Desc | 0 | Land acquisition |
| IRS990/OtherExpensesGrp/Desc | 1 | Land stewardship |
| IRS990/OtherExpensesGrp/Desc | 2 | Printing and Publications |
| IRS990/OtherExpensesGrp/Desc | 3 | Events |
| IRS990/OtherExpensesGrp/FundraisingAmt | 0 | 88058 |
| IRS990/OtherExpensesGrp/FundraisingAmt | 1 | 9234 |
| IRS990/OtherExpensesGrp/ManagementAndGeneralAmt | 0 | 31500 |
| IRS990/OtherExpensesGrp/ManagementAndGeneralAmt | 1 | 76122 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 0 | 4166419 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 1 | 192076 |
| IRS990/OtherExpensesGrp/ProgramServicesAmt | 2 | 64776 |
| IRS990/OtherExpensesGrp/TotalAmt | 0 | 4166419 |
| IRS990/OtherExpensesGrp/TotalAmt | 1 | 192076 |
| IRS990/OtherExpensesGrp/TotalAmt | 2 | 184334 |
| IRS990/OtherExpensesGrp/TotalAmt | 3 | 85356 |
| IRS990/OtherLiabilitiesGrp/BOYAmt | 0 | 287248 |
| IRS990/OtherLiabilitiesGrp/EOYAmt | 0 | 289306 |
| IRS990/OtherRevenueMiscGrp/BusinessCd | 0 | 110000 |
| IRS990/OtherRevenueMiscGrp/Desc | 0 | Settlements - prop damage |
| IRS990/OtherRevenueMiscGrp/RelatedOrExemptFuncIncomeAmt | 0 | 204683 |
| IRS990/OtherRevenueMiscGrp/TotalRevenueColumnAmt | 0 | 204683 |
| IRS990/OtherRevenueTotalAmt | 0 | 204683 |
| IRS990/OtherSalariesAndWagesGrp/FundraisingAmt | 0 | 162509 |
| IRS990/OtherSalariesAndWagesGrp/ManagementAndGeneralAmt | 0 | 49833 |
| IRS990/OtherSalariesAndWagesGrp/ProgramServicesAmt | 0 | 413487 |
| IRS990/OtherSalariesAndWagesGrp/TotalAmt | 0 | 625829 |
| IRS990/OtherWebsiteInd | 0 | X |
| IRS990/OthNotesLoansReceivableNetGrp/EOYAmt | 0 | 0 |
| IRS990/PartialLiquidationInd | 0 | false |
| IRS990/PaymentsToAffiliatesGrp/TotalAmt | 0 | 0 |
| IRS990/PayPremiumsPrsnlBnftCntrctInd | 0 | false |
| IRS990/PayrollTaxesGrp/FundraisingAmt | 0 | 12101 |
| IRS990/PayrollTaxesGrp/ManagementAndGeneralAmt | 0 | 9570 |
| IRS990/PayrollTaxesGrp/ProgramServicesAmt | 0 | 39335 |
| IRS990/PayrollTaxesGrp/TotalAmt | 0 | 61006 |
| IRS990/PensionPlanContributionsGrp/FundraisingAmt | 0 | 5437 |
| IRS990/PensionPlanContributionsGrp/ManagementAndGeneralAmt | 0 | 4300 |
| IRS990/PensionPlanContributionsGrp/ProgramServicesAmt | 0 | 17673 |
| IRS990/PensionPlanContributionsGrp/TotalAmt | 0 | 27410 |
| IRS990/PledgesAndGrantsReceivableGrp/BOYAmt | 0 | 203750 |
| IRS990/PledgesAndGrantsReceivableGrp/EOYAmt | 0 | 232406 |
| IRS990/PoliticalCampaignActyInd | 0 | false |
| IRS990/PrepaidExpensesDefrdChargesGrp/BOYAmt | 0 | 121494 |
| IRS990/PrepaidExpensesDefrdChargesGrp/EOYAmt | 0 | 195057 |
| IRS990/PrincipalOfficerNm | 0 | Linus Eukel |
| IRS990/ProfessionalFundraisingInd | 0 | false |
| IRS990/ProgramServiceRevenueGrp/BusinessCd | 0 | 110000 |
| IRS990/ProgramServiceRevenueGrp/BusinessCd | 1 | 110000 |
| IRS990/ProgramServiceRevenueGrp/BusinessCd | 2 | 110000 |
| IRS990/ProgramServiceRevenueGrp/Desc | 0 | Cell tower |
| IRS990/ProgramServiceRevenueGrp/Desc | 1 | Grazing Revenue |
| IRS990/ProgramServiceRevenueGrp/Desc | 2 | Produce sales |
| IRS990/ProgramServiceRevenueGrp/RelatedOrExemptFuncIncomeAmt | 0 | 28856 |
| IRS990/ProgramServiceRevenueGrp/RelatedOrExemptFuncIncomeAmt | 1 | 18571 |
| IRS990/ProgramServiceRevenueGrp/RelatedOrExemptFuncIncomeAmt | 2 | 1153 |
| IRS990/ProgramServiceRevenueGrp/TotalRevenueColumnAmt | 0 | 28856 |
| IRS990/ProgramServiceRevenueGrp/TotalRevenueColumnAmt | 1 | 18571 |
| IRS990/ProgramServiceRevenueGrp/TotalRevenueColumnAmt | 2 | 1153 |
| IRS990/ProgSrvcAccomActy2Grp/Desc | 0 | Environmental Education and Outreach:Central to JMLT's mission is promoting environmental awareness among residents of the East Bay. We publish newsletters, booklets, and brochures that help everyone appreciate the profound relationship between close-to-home nature and human health and well-being. |
| IRS990/ProgSrvcAccomActy2Grp/ExpenseAmt | 0 | 586889 |
| IRS990/ProhibitedTaxShelterTransInd | 0 | false |
| IRS990/PYContributionsGrantsAmt | 0 | 4711683 |
| IRS990/PYExcessBenefitTransInd | 0 | false |
| IRS990/PYGrantsAndSimilarPaidAmt | 0 | 25000 |
| IRS990/PYInvestmentIncomeAmt | 0 | 9754 |
| IRS990/PymtTravelEntrtnmntPubOfclGrp/TotalAmt | 0 | 0 |
| IRS990/PYOtherExpensesAmt | 0 | 664811 |
| IRS990/PYOtherRevenueAmt | 0 | 648 |
| IRS990/PYProgramServiceRevenueAmt | 0 | 42056 |
| IRS990/PYRevenuesLessExpensesAmt | 0 | 3128051 |