| IRS990/AccountantCompileOrReviewInd | 0 | 0 |
| IRS990/AccountsPayableAccrExpnssGrp/BOYAmt | 0 | 879900 |
| IRS990/AccountsPayableAccrExpnssGrp/EOYAmt | 0 | 1126116 |
| IRS990/ActivitiesConductedPrtshpInd | 0 | 0 |
| IRS990/ActivityOrMissionDesc | 0 | THE COLLEGE PREPARATORY SCHOOL PREPARES STUDENTS FOR COLLEGE AND UNIVERSITY STUDY AND FOR PRODUCTIVE, ETHICAL LIVES. |
| IRS990/AdvertisingGrp/ManagementAndGeneralAmt | 0 | 19584 |
| IRS990/AdvertisingGrp/TotalAmt | 0 | 19584 |
| IRS990/AllOtherContributionsAmt | 0 | 3690297 |
| IRS990/AllOtherExpensesGrp/FundraisingAmt | 0 | 2435 |
| IRS990/AllOtherExpensesGrp/ManagementAndGeneralAmt | 0 | 28384 |
| IRS990/AllOtherExpensesGrp/ProgramServicesAmt | 0 | 180257 |
| IRS990/AllOtherExpensesGrp/TotalAmt | 0 | 211076 |
| IRS990/AnnualDisclosureCoveredPrsnInd | 0 | 1 |
| IRS990/AuditCommitteeInd | 0 | 1 |
| IRS990/BackupWthldComplianceInd | 0 | 1 |
| IRS990/BooksInCareOfDetail/BusinessName/BusinessNameLine1Txt | 0 | CRISTINA MONTEIRO CONTROLLER |
| IRS990/BooksInCareOfDetail/PhoneNum | 0 | 5104202344 |
| IRS990/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | 6100 BROADWAY |
| IRS990/BooksInCareOfDetail/USAddress/CityNm | 0 | OAKLAND |
| IRS990/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | CA |
| IRS990/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 94618 |
| IRS990/BusinessRlnWithFamMemInd | 0 | 0 |
| IRS990/BusinessRlnWithOfficerEntInd | 0 | 0 |
| IRS990/BusinessRlnWithOrgMemInd | 0 | 0 |
| IRS990/CashNonInterestBearingGrp/BOYAmt | 0 | 4517506 |
| IRS990/CashNonInterestBearingGrp/EOYAmt | 0 | 6256315 |
| IRS990/ChangeToOrgDocumentsInd | 0 | 0 |
| IRS990/CntrctRcvdGreaterThan100KCnt | 0 | 5 |
| IRS990/CollectionsOfArtInd | 0 | 0 |
| IRS990/CompCurrentOfcrDirectorsGrp/FundraisingAmt | 0 | 88564 |
| IRS990/CompCurrentOfcrDirectorsGrp/ManagementAndGeneralAmt | 0 | 476686 |
| IRS990/CompCurrentOfcrDirectorsGrp/ProgramServicesAmt | 0 | 132845 |
| IRS990/CompCurrentOfcrDirectorsGrp/TotalAmt | 0 | 698095 |
| IRS990/CompensationFromOtherSrcsInd | 0 | 0 |
| IRS990/CompensationProcessCEOInd | 0 | 1 |
| IRS990/CompensationProcessOtherInd | 0 | 0 |
| IRS990/ConferencesMeetingsGrp/FundraisingAmt | 0 | 100680 |
| IRS990/ConferencesMeetingsGrp/ManagementAndGeneralAmt | 0 | 104665 |
| IRS990/ConferencesMeetingsGrp/ProgramServicesAmt | 0 | 161945 |
| IRS990/ConferencesMeetingsGrp/TotalAmt | 0 | 367290 |
| IRS990/ConflictOfInterestPolicyInd | 0 | 1 |
| IRS990/ConservationEasementsInd | 0 | 0 |
| IRS990/ConsolidatedAuditFinclStmtInd | 0 | 1 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 0 | 764577 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 1 | 288510 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 2 | 241006 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 3 | 197012 |
| IRS990/ContractorCompensationGrp/CompensationAmt | 4 | 150141 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 0 | PO BOX 360170 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 1 | PO BOX 5720 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 2 | 209 HEYERS MILL ROAD |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 3 | 6575-D TRINITY COURT |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/AddressLine1Txt | 4 | 23098 CONNECTICUT STREET |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 0 | PITTSBURGH |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 1 | NAPA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 2 | COLTS NECK |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 3 | DUBLIN |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/CityNm | 4 | HAYWARD |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 0 | PA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 1 | CA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 2 | NJ |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 3 | CA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/StateAbbreviationCd | 4 | CA |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 0 | 15251 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 1 | 94581 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 2 | 07722 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 3 | 94568 |
| IRS990/ContractorCompensationGrp/ContractorAddress/USAddress/ZIPCd | 4 | 94545 |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 0 | SODEXO INC & AFFILIATES |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 1 | BALCAL CONSTRUCTION INC |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 2 | THE WHALEN BEREZ GROUP |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 3 | MOORE MECHANICAL |
| IRS990/ContractorCompensationGrp/ContractorName/BusinessName/BusinessNameLine1Txt | 4 | BLACK DIAMOND PAVING INC |
| IRS990/ContractorCompensationGrp/ServicesDesc | 0 | MAINTENANCE AND CUSTODIAL |
| IRS990/ContractorCompensationGrp/ServicesDesc | 1 | CONSTRUCTION |
| IRS990/ContractorCompensationGrp/ServicesDesc | 2 | CONSTRUCTION |
| IRS990/ContractorCompensationGrp/ServicesDesc | 3 | CONSTRUCTION |
| IRS990/ContractorCompensationGrp/ServicesDesc | 4 | ASPHALT REPAVING |
| IRS990/ContriRptFundraisingEventAmt | 0 | 225885 |
| IRS990/CreditCounselingInd | 0 | 0 |
| IRS990/CYBenefitsPaidToMembersAmt | 0 | 0 |
| IRS990/CYContributionsGrantsAmt | 0 | 3916182 |
| IRS990/CYGrantsAndSimilarPaidAmt | 0 | 2481040 |
| IRS990/CYInvestmentIncomeAmt | 0 | 833168 |
| IRS990/CYOtherExpensesAmt | 0 | 4237034 |
| IRS990/CYOtherRevenueAmt | 0 | -7937 |
| IRS990/CYProgramServiceRevenueAmt | 0 | 15627300 |
| IRS990/CYRevenuesLessExpensesAmt | 0 | 2994126 |
| IRS990/CYSalariesCompEmpBnftPaidAmt | 0 | 10619513 |
| IRS990/CYTotalExpensesAmt | 0 | 17374587 |
| IRS990/CYTotalFundraisingExpenseAmt | 0 | 1112014 |
| IRS990/CYTotalProfFndrsngExpnsAmt | 0 | 37000 |
| IRS990/CYTotalRevenueAmt | 0 | 20368713 |
| IRS990/DecisionsSubjectToApprovaInd | 0 | 0 |
| IRS990/DeductibleArtContributionInd | 0 | 0 |
| IRS990/DeductibleNonCashContriInd | 0 | 1 |
| IRS990/DeferredRevenueGrp/BOYAmt | 0 | 6713215 |
| IRS990/DeferredRevenueGrp/EOYAmt | 0 | 7055419 |
| IRS990/DelegationOfMgmtDutiesInd | 0 | 0 |
| IRS990/DepreciationDepletionGrp/FundraisingAmt | 0 | 44035 |
| IRS990/DepreciationDepletionGrp/ManagementAndGeneralAmt | 0 | 146122 |
| IRS990/DepreciationDepletionGrp/ProgramServicesAmt | 0 | 729964 |
| IRS990/DepreciationDepletionGrp/TotalAmt | 0 | 920121 |
| IRS990/Desc | 0 | THE COLLEGE PREPARATORY SCHOOL IS AN INDEPENDENT, CO-EDUCATIONAL DAY SCHOOL IN OAKLAND, CALIFORNIA, GRADES 9 THROUGH 12. FOR THE 2017-18 SCHOOL YEAR, THE COLLEGE PREPARATORY SCHOOL PROVIDED AN INSPIRING EDUCATION TO 365 STUDENTS, 60% OF WHOM WERE STUDENTS OF COLOR, AND 24% OF WHOM RECEIVED $2.5 MILLION IN NEED-BASED FINANCIAL AID.FOR THE 2017-18 SCHOOL YEAR, THE COLLEGE PREPARATORY SCHOOL GRADUATED AND MATRICULATED 92 SENIORS TO 9 U.S. PUBLIC UNIVERSITIES, 39 U.S. PRIVATE UNIVERSITIES, AND 2 INTERNATIONAL UNIVERSITIES. |
| IRS990/DescribedInSection501c3Ind | 0 | 1 |
| IRS990/DisregardedEntityInd | 0 | 0 |
| IRS990/DocumentRetentionPolicyInd | 0 | 1 |
| IRS990/DonorAdvisedFundInd | 0 | 0 |
| IRS990/ElectionOfBoardMembersInd | 0 | 0 |
| IRS990/EmployeeCnt | 0 | 120 |
| IRS990/EmploymentTaxReturnsFiledInd | 0 | 1 |
| IRS990/EngagedInExcessBenefitTransInd | 0 | 0 |
| IRS990/ExpenseAmt | 0 | 13273502 |
| IRS990/FamilyOrBusinessRlnInd | 0 | 0 |
| IRS990/FederalGrantAuditRequiredInd | 0 | 0 |
| IRS990/FeesForServicesAccountingGrp/ManagementAndGeneralAmt | 0 | 76830 |
| IRS990/FeesForServicesAccountingGrp/TotalAmt | 0 | 76830 |
| IRS990/FeesForServicesLegalGrp/ManagementAndGeneralAmt | 0 | 19991 |
| IRS990/FeesForServicesLegalGrp/TotalAmt | 0 | 19991 |
| IRS990/FeesForServicesOtherGrp/FundraisingAmt | 0 | 24121 |
| IRS990/FeesForServicesOtherGrp/ManagementAndGeneralAmt | 0 | 230821 |
| IRS990/FeesForServicesOtherGrp/ProgramServicesAmt | 0 | 148425 |
| IRS990/FeesForServicesOtherGrp/TotalAmt | 0 | 403367 |
| IRS990/FeesForServicesProfFundraising/FundraisingAmt | 0 | 37000 |
| IRS990/FeesForServicesProfFundraising/TotalAmt | 0 | 37000 |
| IRS990/ForeignActivitiesInd | 0 | 0 |
| IRS990/ForeignFinancialAccountInd | 0 | 0 |
| IRS990/ForeignOfficeInd | 0 | 0 |
| IRS990/Form8282PropertyDisposedOfInd | 0 | 0 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 0 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 1 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 2 | 4.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 3 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 4 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 5 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 6 | 2.00 |
| 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/AverageHoursPerWeekRt | 17 | 2.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 18 | 60.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 19 | 60.00 |
| IRS990/Form990PartVIISectionAGrp/AverageHoursPerWeekRt | 20 | 40.00 |
| 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/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/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/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 | 132262 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 19 | 34516 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 20 | 29028 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 21 | 24357 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 22 | 15308 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 23 | 13318 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 24 | 9111 |
| IRS990/Form990PartVIISectionAGrp/OtherCompensationAmt | 25 | 18694 |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 0 | JIM CERVANTES |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 1 | LAUREN ADAMS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 2 | KEVIN KATARI |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 3 | DICK ATKINSON |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 4 | ALICE CHO |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 5 | KATIE FERRIER |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 6 | AJAY GUPTA |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 7 | JONATHAN HARRIS |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 8 | ADRIENNE HOGG |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 9 | PAM JOHANN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 10 | BRETT JOHNSON |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 11 | SUE LIN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 12 | SARAH MARCHICK |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 13 | TREVA REID |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 14 | ALEXANDER SAH |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 15 | ANEEMA VAN GROENOU |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 16 | JASON WALTHALL |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 17 | RICHARD WHITMORE |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 18 | MONIQUE DEVANE |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 19 | JANE H CARNEY |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 20 | SARA SACKNER |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 21 | MARTIN BONILLA |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 22 | KURT PATZNER |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 23 | SHARONA BARZILAY |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 24 | DAVID KOJAN |
| IRS990/Form990PartVIISectionAGrp/PersonNm | 25 | STEVE CHABON |
| 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 | 381578 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 19 | 231425 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 20 | 186800 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 21 | 168200 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 22 | 166659 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 23 | 161941 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 24 | 159250 |
| IRS990/Form990PartVIISectionAGrp/ReportableCompFromOrgAmt | 25 | 134713 |
| 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/TitleTxt | 0 | TRUSTEE, CHAIR |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 1 | TRUSTEE, VICE CHAIR, SECRE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 2 | TRUSTEE, TREASURER |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 3 | TRUSTEE |
| 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 | HEAD OF SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 19 | CHIEF FINANCIAL OFFICER |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 20 | DIRECTOR OF DEVELOPMENT |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 21 | DIRECTOR OF COLLEGE COUNSE |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 22 | TEACHER |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 23 | TEACHER/ASST. HEAD OF SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 24 | TEACHER/ASST. HEAD OF SCHOOL |
| IRS990/Form990PartVIISectionAGrp/TitleTxt | 25 | DEAN OF STUDENTS |
| IRS990/Form990ProvidedToGvrnBodyInd | 0 | 0 |
| IRS990/FormationYr | 0 | 1960 |
| IRS990/FormerOfcrEmployeesListedInd | 0 | 0 |
| IRS990/FSAuditedBasisGrp/ConsolidatedBasisFinclStmtInd | 0 | X |
| IRS990/FSAuditedInd | 0 | 1 |
| IRS990/FundraisingActivitiesInd | 0 | 1 |
| IRS990/FundraisingAmt | 0 | 225885 |
| IRS990/FundraisingDirectExpensesAmt | 0 | 97992 |
| IRS990/FundraisingGrossIncomeAmt | 0 | 90055 |
| IRS990/GainOrLossGrp/OtherAmt | 0 | -1237 |
| IRS990/GainOrLossGrp/SecuritiesAmt | 0 | 117358 |
| IRS990/GamingActivitiesInd | 0 | 0 |
| IRS990/GoverningBodyVotingMembersCnt | 0 | 18 |
| IRS990/GrantAmt | 0 | 2481040 |
| IRS990/GrantsToDomesticIndividualsGrp/ProgramServicesAmt | 0 | 2432040 |
| IRS990/GrantsToDomesticIndividualsGrp/TotalAmt | 0 | 2432040 |
| IRS990/GrantsToDomesticOrgsGrp/ProgramServicesAmt | 0 | 49000 |
| IRS990/GrantsToDomesticOrgsGrp/TotalAmt | 0 | 49000 |
| IRS990/GrantsToIndividualsInd | 0 | 1 |
| IRS990/GrantsToOrganizationsInd | 0 | 1 |
| IRS990/GrantToRelatedPersonInd | 0 | 0 |
| IRS990/GrossAmountSalesAssetsGrp/SecuritiesAmt | 0 | 1034087 |
| IRS990/GrossReceiptsAmt | 0 | 21384671 |
| IRS990/GroupReturnForAffiliatesInd | 0 | 0 |
| IRS990/IncludeFIN48FootnoteInd | 0 | 1 |
| IRS990/IndependentAuditFinclStmtInd | 0 | 0 |
| IRS990/IndependentVotingMemberCnt | 0 | 18 |
| IRS990/IndivRcvdGreaterThan100KCnt | 0 | 29 |
| IRS990/IndoorTanningServicesInd | 0 | 0 |
| IRS990/InfoInScheduleOPartIIIInd | 0 | X |
| IRS990/InfoInScheduleOPartVIInd | 0 | X |
| IRS990/InfoInScheduleOPartXIIInd | 0 | X |
| IRS990/InformationTechnologyGrp/FundraisingAmt | 0 | 30158 |
| IRS990/InformationTechnologyGrp/ManagementAndGeneralAmt | 0 | 12342 |
| IRS990/InformationTechnologyGrp/ProgramServicesAmt | 0 | 313900 |
| IRS990/InformationTechnologyGrp/TotalAmt | 0 | 356400 |
| IRS990/InsuranceGrp/FundraisingAmt | 0 | 979 |
| IRS990/InsuranceGrp/ManagementAndGeneralAmt | 0 | 204066 |
| IRS990/InsuranceGrp/TotalAmt | 0 | 205045 |
| IRS990/InterestGrp/FundraisingAmt | 0 | 5041 |
| IRS990/InterestGrp/ManagementAndGeneralAmt | 0 | 28565 |
| IRS990/InterestGrp/TotalAmt | 0 | 33606 |
| IRS990/InvestmentIncomeGrp/ExclusionAmt | 0 | 717047 |
| IRS990/InvestmentIncomeGrp/TotalRevenueColumnAmt | 0 | 717047 |
| IRS990/InvestmentInJointVentureInd | 0 | 0 |
| IRS990/InvestmentsPubTradedSecGrp/BOYAmt | 0 | 22380696 |
| IRS990/InvestmentsPubTradedSecGrp/EOYAmt | 0 | 23796342 |
| IRS990/IRPDocumentCnt | 0 | 43 |
| IRS990/IRPDocumentW2GCnt | 0 | 0 |
| IRS990/LandBldgEquipAccumDeprecAmt | 0 | 9443816 |
| IRS990/LandBldgEquipBasisNetGrp/BOYAmt | 0 | 13177681 |
| IRS990/LandBldgEquipBasisNetGrp/EOYAmt | 0 | 13432917 |
| IRS990/LandBldgEquipCostOrOtherBssAmt | 0 | 22876733 |
| IRS990/LegalDomicileStateCd | 0 | CA |
| IRS990/LessCostOthBasisSalesExpnssGrp/OtherAmt | 0 | 1237 |
| IRS990/LessCostOthBasisSalesExpnssGrp/SecuritiesAmt | 0 | 916729 |
| 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 | AT COLLEGE PREP WE BELIEVE IN THE FOUNDATIONAL IMPORTANCE OF SCHOLARSHIP, THE VALUE OF DIALOGUE, AND THE NEED FOR ACADEMICALLY CURIOUS YOUNG PEOPLE TO BELONG TO A KIND, CREATIVE, DIVERSE, AND JOYFUL COMMUNITY. WE CHALLENGE OUR STUDENTS TO ENGAGE DEEPLY IN LEARNING, APPRECIATE ONE ANOTHER, AND GROW INTO ADULTS WHO ARE INTELLECTUALLY ADVENTUROUS, ETHICALLY SURE-FOOTED, AND GENEROUS OF HEART AND SPIRIT. |
| IRS990/MoreThan5000KToIndividualsInd | 0 | 0 |
| IRS990/MoreThan5000KToOrgInd | 0 | 0 |
| IRS990/MortgNotesPyblScrdInvstPropGrp/BOYAmt | 0 | 804832 |
| IRS990/MortgNotesPyblScrdInvstPropGrp/EOYAmt | 0 | 749851 |
| IRS990/NetAssetsOrFundBalancesBOYAmt | 0 | 40271561 |
| IRS990/NetAssetsOrFundBalancesEOYAmt | 0 | 44362340 |
| IRS990/NetGainOrLossInvestmentsGrp/ExclusionAmt | 0 | 116121 |
| IRS990/NetGainOrLossInvestmentsGrp/TotalRevenueColumnAmt | 0 | 116121 |
| IRS990/NetIncmFromFundraisingEvtGrp/ExclusionAmt | 0 | -7937 |
| IRS990/NetIncmFromFundraisingEvtGrp/TotalRevenueColumnAmt | 0 | -7937 |
| IRS990/NetUnrelatedBusTxblIncmAmt | 0 | 0 |
| IRS990/NetUnrlzdGainsLossesInvstAmt | 0 | 1096653 |
| IRS990/NoncashContributionsAmt | 0 | 1088266 |
| IRS990/NondeductibleContributionsInd | 0 | 0 |
| IRS990/OccupancyGrp/FundraisingAmt | 0 | 39392 |
| IRS990/OccupancyGrp/ManagementAndGeneralAmt | 0 | 107928 |
| IRS990/OccupancyGrp/ProgramServicesAmt | 0 | 908743 |
| IRS990/OccupancyGrp/TotalAmt | 0 | 1056063 |
| IRS990/OfficeExpensesGrp/FundraisingAmt | 0 | 50400 |
| IRS990/OfficeExpensesGrp/ManagementAndGeneralAmt | 0 | 40617 |
| IRS990/OfficeExpensesGrp/ProgramServicesAmt | 0 | 65871 |