| IRS990/AccountantCompileOrReviewInd | 0 | 0 |
| IRS990/AccountsPayableAccrExpnssGrp/BOYAmt | 0 | 2466106 |
| IRS990/AccountsPayableAccrExpnssGrp/EOYAmt | 0 | 2920835 |
| IRS990/AccountsReceivableGrp/BOYAmt | 0 | 98265 |
| IRS990/AccountsReceivableGrp/EOYAmt | 0 | 232290 |
| IRS990/ActivitiesConductedPrtshpInd | 0 | 0 |
| IRS990/ActivityOrMissionDesc | 0 | BENTLEY SCHOOL IS A COEDUCATIONAL DAY SCHOOL, GRADES K-12. |
| IRS990/AdvertisingGrp/ManagementAndGeneralAmt | 0 | 17272 |
| IRS990/AdvertisingGrp/ProgramServicesAmt | 0 | 49113 |
| IRS990/AdvertisingGrp/TotalAmt | 0 | 66385 |
| IRS990/AllOtherContributionsAmt | 0 | 1195018 |
| IRS990/AnnualDisclosureCoveredPrsnInd | 0 | 1 |
| IRS990/AuditCommitteeInd | 0 | 1 |
| IRS990/BackupWthldComplianceInd | 0 | 1 |
| IRS990/BooksInCareOfDetail/BusinessName/BusinessNameLine1Txt | 0 | THAM TRUONG CONTROLLER |
| IRS990/BooksInCareOfDetail/PhoneNum | 0 | 9259004086 |
| IRS990/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | 1000 UPPER HAPPY VALLEY RD |
| IRS990/BooksInCareOfDetail/USAddress/CityNm | 0 | LAFAYETTE |
| IRS990/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | CA |
| IRS990/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 94549 |
| IRS990/BusinessRlnWithFamMemInd | 0 | 0 |
| IRS990/BusinessRlnWithOfficerEntInd | 0 | 0 |
| IRS990/BusinessRlnWithOrgMemInd | 0 | 0 |
| IRS990/CashNonInterestBearingGrp/BOYAmt | 0 | 13651134 |
| IRS990/CashNonInterestBearingGrp/EOYAmt | 0 | 13941578 |
| IRS990/ChangeToOrgDocumentsInd | 0 | 0 |
| IRS990/CntrctRcvdGreaterThan100KCnt | 0 | 2 |
| IRS990/CollectionsOfArtInd | 0 | 0 |
| IRS990/CompCurrentOfcrDirectorsGrp/FundraisingAmt | 0 | 89796 |
| IRS990/CompCurrentOfcrDirectorsGrp/ManagementAndGeneralAmt | 0 | 591116 |
| IRS990/CompCurrentOfcrDirectorsGrp/ProgramServicesAmt | 0 | 227925 |
| IRS990/CompCurrentOfcrDirectorsGrp/TotalAmt | 0 | 908837 |
| IRS990/CompensationFromOtherSrcsInd | 0 | 0 |
| IRS990/CompensationProcessCEOInd | 0 | 1 |
| IRS990/CompensationProcessOtherInd | 0 | 1 |
| IRS990/ConferencesMeetingsGrp/FundraisingAmt | 0 | 51543 |
| IRS990/ConferencesMeetingsGrp/ManagementAndGeneralAmt | 0 | 98081 |
| IRS990/ConferencesMeetingsGrp/ProgramServicesAmt | 0 | 146512 |
| IRS990/ConferencesMeetingsGrp/TotalAmt | 0 | 296136 |
| IRS990/ConflictOfInterestPolicyInd | 0 | 1 |
| IRS990/ConservationEasementsInd | 0 | 0 |
| IRS990/ConsolidatedAuditFinclStmtInd | 0 | 0 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 0 | 306737 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 1 | 224159 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 0 | 5029 FORNI DR |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 1 | 508 MONOGRAM RD |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 0 | CONCORD |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 1 | SAN LEANDRO |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 0 | CA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 1 | CA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 0 | 94520 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 1 | 94577 |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 0 | DURHAM SCHOOL SERVICE |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 1 | MMM GENERAL CONTRACTOR |
| IRS990/ContractorCompensationGrp/ServicesDesc | 0 | BUS SERVICE |
| IRS990/ContractorCompensationGrp/ServicesDesc | 1 | CONSTRUCTION |
| IRS990/ContriRptFundraisingEventAmt | 0 | 226182 |
| IRS990/CreditCounselingInd | 0 | 0 |
| IRS990/CYBenefitsPaidToMembersAmt | 0 | 0 |
| IRS990/CYContributionsGrantsAmt | 0 | 1421200 |
| IRS990/CYGrantsAndSimilarPaidAmt | 0 | 3372776 |
| IRS990/CYInvestmentIncomeAmt | 0 | 139501 |
| IRS990/CYOtherExpensesAmt | 0 | 8960309 |
| IRS990/CYOtherRevenueAmt | 0 | 37142 |
| IRS990/CYProgramServiceRevenueAmt | 0 | 25736401 |
| IRS990/CYRevenuesLessExpensesAmt | 0 | -148313 |
| IRS990/CYSalariesCompEmpBnftPaidAmt | 0 | 15149472 |
| IRS990/CYTotalExpensesAmt | 0 | 27482557 |
| IRS990/CYTotalFundraisingExpenseAmt | 0 | 902668 |
| IRS990/CYTotalProfFndrsngExpnsAmt | 0 | 0 |
| IRS990/CYTotalRevenueAmt | 0 | 27334244 |
| IRS990/DecisionsSubjectToApprovaInd | 0 | 0 |
| IRS990/DeductibleArtContributionInd | 0 | 0 |
| IRS990/DeductibleNonCashContriInd | 0 | 0 |
| IRS990/DeferredRevenueGrp/BOYAmt | 0 | 13951477 |
| IRS990/DeferredRevenueGrp/EOYAmt | 0 | 13799690 |
| IRS990/DelegationOfMgmtDutiesInd | 0 | 0 |
| IRS990/DepreciationDepletionGrp/ProgramServicesAmt | 0 | 1398755 |
| IRS990/DepreciationDepletionGrp/TotalAmt | 0 | 1398755 |
| IRS990/Desc | 0 | BENTLEY SCHOOL SERVES STUDENTS ON TWO CAMPUSES. THE OAKLAND, CALIFORNIA, CAMPUS SERVES APPROXIMATELY 349 K-8 STUDENTS AND THE LAFAYETTE, CALIFORNIA, CAMPUS SERVES APPROXIMATELY 345 HIGH SCHOOL STUDENTS. THE SCHOOL IS ACCREDITED BY THE CALIFORNIA ASSOCIATION OF INDEPENDENT SCHOOLS. |
| IRS990/DescribedInSection501c3Ind | 0 | 1 |
| IRS990/DisregardedEntityInd | 0 | 0 |
| IRS990/DocumentRetentionPolicyInd | 0 | 1 |
| IRS990/DonorAdvisedFundInd | 0 | 0 |
| IRS990/ElectionOfBoardMembersInd | 0 | 0 |
| IRS990/EmployeeCnt | 0 | 251 |
| IRS990/EmploymentTaxReturnsFiledInd | 0 | 1 |
| IRS990/EngagedInExcessBenefitTransInd | 0 | 0 |
| IRS990/EscrowAccountInd | 0 | 0 |
| IRS990/ExpenseAmt | 0 | 21946456 |
| IRS990/FamilyOrBusinessRlnInd | 0 | 0 |
| IRS990/FederalGrantAuditRequiredInd | 0 | 0 |
| IRS990/FeesForServicesAccountingGrp/ManagementAndGeneralAmt | 0 | 57500 |
| IRS990/FeesForServicesAccountingGrp/TotalAmt | 0 | 57500 |
| IRS990/FeesForServicesLegalGrp/ManagementAndGeneralAmt | 0 | 167661 |
| IRS990/FeesForServicesLegalGrp/TotalAmt | 0 | 167661 |
| IRS990/FeesForServicesManagementGrp/ManagementAndGeneralAmt | 0 | 525585 |
| IRS990/FeesForServicesManagementGrp/TotalAmt | 0 | 525585 |
| IRS990/ForeignActivitiesInd | 0 | 0 |
| IRS990/ForeignFinancialAccountInd | 0 | 0 |
| IRS990/ForeignOfficeInd | 0 | 0 |
| IRS990/Form8282PropertyDisposedOfInd | 0 | 0 |
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| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 1 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 2 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 3 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 4 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 5 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 6 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 7 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 8 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 9 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 10 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 11 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 12 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 13 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 14 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 15 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 16 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 17 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 18 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 19 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 20 | 3.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 21 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 22 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 23 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 24 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 25 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 26 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 27 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 28 | 40.00 |
| IRS990/Form990PartVIISectionAGrp/HighestCompensatedEmployeeInd | 0 | X |
| IRS990/Form990PartVIISectionAGrp/HighestCompensatedEmployeeInd | 1 | X |
| IRS990/Form990PartVIISectionAGrp/HighestCompensatedEmployeeInd | 2 | X |
| IRS990/Form990PartVIISectionAGrp/HighestCompensatedEmployeeInd | 3 | X |
| IRS990/Form990PartVIISectionAGrp/HighestCompensatedEmployeeInd | 4 | X |
| 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/IndividualTrusteeOrDirectorInd | 14 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 15 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 16 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 17 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 18 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 19 | X |
| IRS990/Form990PartVIISectionAGrp/IndividualTrusteeOrDirectorInd | 20 | X |
| IRS990/Form990PartVIISectionAGrp/KeyEmployeeInd | 0 | 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 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 1 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 2 | 0 |
| 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/OtherCompensationAmt | 17 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 18 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 19 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 20 | 0 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 21 | 139742 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 22 | 22533 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 23 | 18829 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 24 | 19741 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 25 | 18618 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 26 | 17363 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 27 | 16595 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 28 | 16663 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 0 | MICHAEL HUGHES |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 1 | HELENE JEPSON |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 2 | LUCINDA IGARASHI |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 3 | DAVID KAPLAN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 4 | DAVE HUMMEL |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 5 | JODI NOACK |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 6 | MILT CAPSIMALIS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 7 | JORDAN MONCHARMONT |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 8 | SHANKAR SASTRY |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 9 | JOHN FOSTER - FROM 618 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 10 | EDWARD SMITH - FROM 618 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 11 | SCOTT WESSEL - FROM 618 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 12 | FRANK WITNEY |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 13 | JAY BHALLA |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 14 | RICK CLARKE |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 15 | SCOTT SILLERS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 16 | LISA VIOLET |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 17 | NICOLE PITTS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 18 | MICHAEL BROWN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 19 | GARY JUNG |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 20 | JAMES KADLECK |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 21 | ARLENE HOGAN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 22 | ALEXANDER KOPELEVICH |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 23 | BRYAN SMITH |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 24 | CAROL SWAINSON |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 25 | LISA LOMBA |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 26 | ARCHIBALD DOUGLAS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 27 | INA-KATRIN STAHL |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 28 | CHRISTINA CHECOVICH |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 0 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 1 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 2 | 0 |
| 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/ReportableCompFromOrgAmt | 17 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 18 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 19 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 20 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 21 | 412698 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 22 | 230010 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 23 | 165425 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 24 | 159930 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 25 | 158471 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 26 | 152869 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 27 | 139318 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 28 | 133002 |
| 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/ReportableCompFromRltdOrgAmt | 17 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 18 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 19 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 20 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 21 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 22 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 23 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 24 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 25 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 26 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 27 | 0 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromRltdOrgAmt | 28 | 0 |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 0 | BOARD CHAIR |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 1 | VICE PRESIDENT |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 2 | SECRETARY |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 3 | TREASURER |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 4 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 5 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 6 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 7 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 8 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 9 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 10 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 11 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 12 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 13 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 14 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 15 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 16 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 17 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 18 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 19 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 20 | TRUSTEE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 21 | HEAD OF SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 22 | CFO/COO |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 23 | HEAD OF UPPER SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 24 | HEAD OF LOWER SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 25 | DIR. OF EXTERNAL RELATIONS |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 26 | DIR. OF COLLEGE COUNSELING |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 27 | CONTROLLER |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 28 | DIR. OF ADMISSIONS AND FIN |
| IRS990/Form990ProvidedToGvrnBodyInd | 0 | 1 |
| IRS990/Form990TFiledInd | 0 | 1 |
| IRS990/FormationYr | 0 | 1969 |
| IRS990/FormerOfcrEmployeesListedInd | 0 | 0 |
| IRS990/FSAuditedBasisGrp/SeparateBasisFinclStmtInd | 0 | X |
| IRS990/FSAuditedInd | 0 | 1 |
| IRS990/FundraisingActivitiesInd | 0 | 1 |
| IRS990/FundraisingAmt | 0 | 226182 |
| IRS990/FundraisingDirectExpensesAmt | 0 | 97446 |
| IRS990/FundraisingGrossIncomeAmt | 0 | 102347 |
| IRS990/GainOrLossGrp/OtherAmt | 0 | 200 |
| IRS990/GamingActivitiesInd | 0 | 0 |
| IRS990/GoverningBodyVotingMembersCnt | 0 | 15 |
| IRS990/GrantAmt | 0 | 3372776 |
| IRS990/GrantsToDomesticIndividualsGrp/ProgramServicesAmt | 0 | 3372776 |
| IRS990/GrantsToDomesticIndividualsGrp/TotalAmt | 0 | 3372776 |
| IRS990/GrantsToIndividualsInd | 0 | 1 |
| IRS990/GrantsToOrganizationsInd | 0 | 0 |
| IRS990/GrantToRelatedPersonInd | 0 | 0 |
| IRS990/GrossAmountSalesAssetsGrp/OtherAmt | 0 | 200 |
| IRS990/GrossReceiptsAmt | 0 | 27431690 |
| IRS990/GroupReturnForAffiliatesInd | 0 | 0 |
| IRS990/IncludeFIN48FootnoteInd | 0 | 1 |
| IRS990/IndependentAuditFinclStmtInd | 0 | 1 |
| IRS990/IndependentVotingMemberCnt | 0 | 15 |
| IRS990/IndivRcvdGreaterThan100KCnt | 0 | 23 |
| IRS990/IndoorTanningServicesInd | 0 | 0 |
| IRS990/InfoInScheduleOPartIIIInd | 0 | X |
| IRS990/InfoInScheduleOPartVIInd | 0 | X |
| IRS990/InfoInScheduleOPartXIIInd | 0 | X |
| IRS990/InsuranceGrp/FundraisingAmt | 0 | 1302 |
| IRS990/InsuranceGrp/ManagementAndGeneralAmt | 0 | 6684 |
| IRS990/InsuranceGrp/ProgramServicesAmt | 0 | 26793 |
| IRS990/InsuranceGrp/TotalAmt | 0 | 34779 |
| IRS990/IntangibleAssetsGrp/BOYAmt | 0 | 271502 |
| IRS990/IntangibleAssetsGrp/EOYAmt | 0 | 259698 |
| IRS990/InterestGrp/ManagementAndGeneralAmt | 0 | 341833 |
| IRS990/InterestGrp/ProgramServicesAmt | 0 | 1436876 |
| IRS990/InterestGrp/TotalAmt | 0 | 1778709 |
| IRS990/InvestmentIncomeGrp/ExclusionAmt | 0 | 139301 |
| IRS990/InvestmentIncomeGrp/TotalRevenueColumnAmt | 0 | 139301 |
| IRS990/InvestmentInJointVentureInd | 0 | 0 |
| IRS990/InvestmentsPubTradedSecGrp/BOYAmt | 0 | 989571 |
| IRS990/InvestmentsPubTradedSecGrp/EOYAmt | 0 | 1122002 |
| IRS990/InvestTaxExemptBondsInd | 0 | 0 |
| IRS990/IRPDocumentCnt | 0 | 101 |
| IRS990/IRPDocumentW2GCnt | 0 | 0 |
| IRS990/LandBldgEquipAccumDeprecAmt | 0 | 21692241 |
| IRS990/LandBldgEquipBasisNetGrp/BOYAmt | 0 | 21939551 |
| IRS990/LandBldgEquipBasisNetGrp/EOYAmt | 0 | 21743815 |
| IRS990/LandBldgEquipCostOrOtherBssAmt | 0 | 43436056 |
| IRS990/LegalDomicileStateCd | 0 | CA |
| IRS990/LessCostOthBasisSalesExpnssGrp/OtherAmt | 0 | 0 |
| IRS990/LoanOutstandingInd | 0 | 0 |
| IRS990/LobbyingActivitiesInd | 0 | 0 |
| IRS990/LocalChaptersInd | 0 | 0 |
| IRS990/MaterialDiversionOrMisuseInd | 0 | 0 |
| IRS990/MembersOrStockholdersInd | 0 | 0 |
| IRS990/MethodOfAccountingAccrualInd | 0 | X |
| IRS990/MinutesOfCommitteesInd | 0 | 1 |
| IRS990/MinutesOfGoverningBodyInd | 0 | 1 |
| IRS990/MissionDesc | 0 | BENTLEY SCHOOL IS A COEDUCATIONAL DAY SCHOOL, GRADES K-12. THE MISSION OF THE SCHOOL IS TO INSPIRE INQUIRY, ACADEMIC EXCELLENCE, PERSONAL ACHIEVEMENT, AND CHARACTER BY ENGAGING STUDENTS' INTELLECT AND CREATIVITY, AND BY ENCOURAGING THEM TO EMBRACE VALUES THAT ENRICH THEIR COMMUNITY AND THE WORLD. |
| IRS990/MoreThan5000KToIndividualsInd | 0 | 0 |
| IRS990/MoreThan5000KToOrgInd | 0 | 0 |
| IRS990/NetAssetsOrFundBalancesBOYAmt | 0 | -304466 |
| IRS990/NetAssetsOrFundBalancesEOYAmt | 0 | -411203 |
| IRS990/NetGainOrLossInvestmentsGrp/ExclusionAmt | 0 | 200 |
| IRS990/NetGainOrLossInvestmentsGrp/TotalRevenueColumnAmt | 0 | 200 |
| IRS990/NetIncmFromFundraisingEvtGrp/ExclusionAmt | 0 | 4901 |
| IRS990/NetIncmFromFundraisingEvtGrp/TotalRevenueColumnAmt | 0 | 4901 |
| IRS990/NetUnrelatedBusTxblIncmAmt | 0 | 466 |
| IRS990/NetUnrlzdGainsLossesInvstAmt | 0 | 41576 |
| IRS990/NoncashContributionsAmt | 0 | 5307 |
| IRS990/NondeductibleContributionsInd | 0 | 0 |
| IRS990/OccupancyGrp/FundraisingAmt | 0 | 51895 |
| IRS990/OccupancyGrp/ManagementAndGeneralAmt | 0 | 37864 |
| IRS990/OccupancyGrp/ProgramServicesAmt | 0 | 2719502 |
| IRS990/OccupancyGrp/TotalAmt | 0 | 2809261 |
| IRS990/OfficeExpensesGrp/FundraisingAmt | 0 | 97208 |
| IRS990/OfficeExpensesGrp/ManagementAndGeneralAmt | 0 | 23180 |
| IRS990/OfficeExpensesGrp/ProgramServicesAmt | 0 | 47193 |
| IRS990/OfficeExpensesGrp/TotalAmt | 0 | 167581 |
| IRS990/OfficerMailingAddressInd | 0 | 0 |
| IRS990/OnBehalfOfIssuerInd | 0 | 0 |
| IRS990/OperateHospitalInd | 0 | 0 |
| IRS990/Organization501c3Ind | 0 | X |
| IRS990/OrganizationFollowsSFAS117Ind | 0 | X |
| IRS990/OtherChangesInNetAssetsAmt | 0 | 0 |
| IRS990/OtherEmployeeBenefitsGrp/FundraisingAmt | 0 | 48323 |
| IRS990/OtherEmployeeBenefitsGrp/ManagementAndGeneralAmt | 0 | 299898 |
| IRS990/OtherEmployeeBenefitsGrp/ProgramServicesAmt | 0 | 975955 |