<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>750</ContextCount>
  <ElementCount>761</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>228</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>16</UnitCount>
  <MyReports>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Document - Audit Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AuditInformation</Role>
      <ShortName>Audit Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedStatementsofOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedStatementsofComprehensiveIncomeLoss</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Balance Sheets (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedBalanceSheetsParentheticals</Role>
      <ShortName>Consolidated Balance Sheets (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952155 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952156 - Statement - Consolidated Statements of Changes in Common Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ConsolidatedStatementsofChangesinCommonShareholdersEquity</Role>
      <ShortName>Consolidated Statements of Changes in Common Shareholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Organization and Nature of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OrganizationandNatureofOperations</Role>
      <ShortName>Organization and Nature of Operations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Acquisitions and Dispositions of Businesses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinesses</Role>
      <ShortName>Acquisitions and Dispositions of Businesses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/Investments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilities</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Inventories and Contracts in Progress</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InventoriesandContractsinProgress</Role>
      <ShortName>Inventories and Contracts in Progress</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Property, Plant and Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PropertyPlantandEquipment</Role>
      <ShortName>Property, Plant and Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssets</Role>
      <ShortName>Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Revenue from Contracts with Customers</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractswithCustomers</Role>
      <ShortName>Revenue from Contracts with Customers</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Capital Stock, Stock Awards, and Stock Options</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - Pensions and Other Postretirement Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlans</Role>
      <ShortName>Pensions and Other Postretirement Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - Other Non-Operating (Expense) Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OtherNonOperatingExpenseIncome</Role>
      <ShortName>Other Non-Operating (Expense) Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - Accumulated Other Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLoss</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9952174 - Disclosure - Contingencies and Other Commitments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ContingenciesandOtherCommitments</Role>
      <ShortName>Contingencies and Other Commitments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9952175 - Disclosure - Business Segments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/BusinessSegments</Role>
      <ShortName>Business Segments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995447 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Summary of Significant Accounting Policies (Policy)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/SummaryofSignificantAccountingPoliciesPolicy</Role>
      <ShortName>Summary of Significant Accounting Policies (Policy)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.ghco.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - Acquisitions and Dispositions of Businesses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesTables</Role>
      <ShortName>Acquisitions and Dispositions of Businesses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinesses</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/Investments</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilities</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Inventories and Contracts in Progress (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InventoriesandContractsinProgressTables</Role>
      <ShortName>Inventories and Contracts in Progress (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/InventoriesandContractsinProgress</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Property, Plant and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PropertyPlantandEquipmentTables</Role>
      <ShortName>Property, Plant and Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PropertyPlantandEquipment</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/Leases</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssets</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxes</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/Debt</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/FairValueMeasurements</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Revenue from Contracts with Customers (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractswithCustomersTables</Role>
      <ShortName>Revenue from Contracts with Customers (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/RevenuefromContractswithCustomers</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Capital Stock, Stock Awards and Stock Options (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsTables</Role>
      <ShortName>Capital Stock, Stock Awards and Stock Options (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Pensions and Other Postretirement Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</Role>
      <ShortName>Pensions and Other Postretirement Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlans</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - Other Non-Operating (Expense) Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OtherNonOperatingExpenseIncomeTables</Role>
      <ShortName>Other Non-Operating (Expense) Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/OtherNonOperatingExpenseIncome</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLoss</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - Business Segments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/BusinessSegmentsTables</Role>
      <ShortName>Business Segments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ghco.com/role/BusinessSegments</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Organization and Nature of Operations (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OrganizationandNatureofOperationsNarrativeDetails</Role>
      <ShortName>Organization and Nature of Operations (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/OrganizationandNatureofOperations</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Summary of Significant Accounting Policies (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Summary of Significant Accounting Policies (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/SummaryofSignificantAccountingPoliciesPolicy</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Acquisitions and Dispositions of Businesses (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesNarrativeDetails</Role>
      <ShortName>Acquisitions and Dispositions of Businesses (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Acquisitions and Dispositions of Businesses (Assets Acquired and Liabilities Assumed) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesAssetsAcquiredandLiabilitiesAssumedDetails1</Role>
      <ShortName>Acquisitions and Dispositions of Businesses (Assets Acquired and Liabilities Assumed) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - Acquisitions and Dispositions of Businesses (Pro Forma Financials) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesProFormaFinancialsDetails2</Role>
      <ShortName>Acquisitions and Dispositions of Businesses (Pro Forma Financials) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AcquisitionsandDispositionsofBusinessesTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Investments (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InvestmentsNarrativeDetails</Role>
      <ShortName>Investments (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/InvestmentsTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Investments (Investments in Marketable Equity Securities) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InvestmentsInvestmentsinMarketableEquitySecuritiesDetails1</Role>
      <ShortName>Investments (Investments in Marketable Equity Securities) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/InvestmentsTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Investments Gain (Loss) on Marketable Equity Securities) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InvestmentsGainLossonMarketableEquitySecuritiesDetails2</Role>
      <ShortName>Investments Gain (Loss) on Marketable Equity Securities) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesNarrativeDetails</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Accounts Receivable) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesScheduleofAccountsReceivableDetails1</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Accounts Receivable) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Changes in Estimated Credit Losses) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesScheduleofChangesinEstimatedCreditLossesDetails2</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Changes in Estimated Credit Losses) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities) (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesScheduleofAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesDetails3</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Schedule of Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities) (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Supplier Finance Program Reconciliation) (Details 4)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesSupplierFinanceProgramReconciliationDetails4</Role>
      <ShortName>Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities (Supplier Finance Program Reconciliation) (Details 4)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccountsReceivableAccountsPayableVehicleFloorPlanPayableandAccruedLiabilitiesTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Inventories and Contracts in Progress (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/InventoriesandContractsinProgressDetails</Role>
      <ShortName>Inventories and Contracts in Progress (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/InventoriesandContractsinProgressTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Property, Plant and Equipment (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PropertyPlantandEquipmentNarrativeDetails</Role>
      <ShortName>Property, Plant and Equipment (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PropertyPlantandEquipmentTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PropertyPlantandEquipmentDetails</Role>
      <ShortName>Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PropertyPlantandEquipmentTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - Leases (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesNarrativeDetails</Role>
      <ShortName>Leases (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/LeasesTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - Leases (Components of Lease Expense) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesComponentsofLeaseExpenseDetails</Role>
      <ShortName>Leases (Components of Lease Expense) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/LeasesTables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - Leases (Supplemental Balance Sheet Information Related to Leases) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesSupplementalBalanceSheetInformationRelatedtoLeasesDetails</Role>
      <ShortName>Leases (Supplemental Balance Sheet Information Related to Leases) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/LeasesTables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - Leases (Maturities of Lease Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesMaturitiesofLeaseLiabilitiesDetails</Role>
      <ShortName>Leases (Maturities of Lease Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/LeasesTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - Leases (Supplemental Cash Flow Information Related to Leases) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/LeasesSupplementalCashFlowInformationRelatedtoLeasesDetails</Role>
      <ShortName>Leases (Supplemental Cash Flow Information Related to Leases) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/LeasesTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - Goodwill and Other Intangible Assets (Goodwill) (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsGoodwillNarrativeDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets (Goodwill) (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>9955551 - Disclosure - Goodwill and Other Intangible Assets (Indefinite-lived Intangible Assets) (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsIndefinitelivedIntangibleAssetsNarrativeDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets (Indefinite-lived Intangible Assets) (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>9955552 - Disclosure - Goodwill and Other Intangible Assets (Finite-lived Intangible Assets) (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsFinitelivedIntangibleAssetsNarrativeDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets (Finite-lived Intangible Assets) (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>9955553 - Disclosure - Goodwill and Other Intangible Assets (Changes in Carrying Amount of Goodwill) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsChangesinCarryingAmountofGoodwillDetails1</Role>
      <ShortName>Goodwill and Other Intangible Assets (Changes in Carrying Amount of Goodwill) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>9955554 - Disclosure - Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsOtherIntangibleAssetsDetails2</Role>
      <ShortName>Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>9955555 - Disclosure - Income Taxes (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesNarrativeDetails</Role>
      <ShortName>Income Taxes (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>9955556 - Disclosure - Income Taxes (Income from Operations) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesIncomefromOperationsDetails1</Role>
      <ShortName>Income Taxes (Income from Operations) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>9955557 - Disclosure - Income Taxes (Provision for Income Taxes Components) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesProvisionforIncomeTaxesComponentsDetails2</Role>
      <ShortName>Income Taxes (Provision for Income Taxes Components) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>9955558 - Disclosure - Income Taxes (Income Tax Reconciliation) (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesIncomeTaxReconciliationDetails3</Role>
      <ShortName>Income Taxes (Income Tax Reconciliation) (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>9955559 - Disclosure - Income Taxes (Deferred Income Taxes Components) (Details 4)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesDeferredIncomeTaxesComponentsDetails4</Role>
      <ShortName>Income Taxes (Deferred Income Taxes Components) (Details 4)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>9955560 - Disclosure - Income Taxes (Income Taxes Paid) (Details 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesIncomeTaxesPaidDetails5</Role>
      <ShortName>Income Taxes (Income Taxes Paid) (Details 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>9955561 - Disclosure - Income Taxes (Operating Loss Carryforwards) (Details 6)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesOperatingLossCarryforwardsDetails6</Role>
      <ShortName>Income Taxes (Operating Loss Carryforwards) (Details 6)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>9955562 - Disclosure - Income Taxes (Deferred Tax Valuation Allowances) (Details 7)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesDeferredTaxValuationAllowancesDetails7</Role>
      <ShortName>Income Taxes (Deferred Tax Valuation Allowances) (Details 7)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>9955563 - Disclosure - Income Taxes (Unrecognized Tax Benefits Rollforward) (Details 8)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/IncomeTaxesUnrecognizedTaxBenefitsRollforwardDetails8</Role>
      <ShortName>Income Taxes (Unrecognized Tax Benefits Rollforward) (Details 8)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/IncomeTaxesTables</ParentRole>
      <Position>82</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>9955564 - Disclosure - Debt (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/DebtNarrativeDetails</Role>
      <ShortName>Debt (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/DebtTables</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>9955565 - Disclosure - Debt (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/DebtDetails1</Role>
      <ShortName>Debt (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/DebtTables</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>9955566 - Disclosure - Fair Value Measurements (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/FairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Fair Value Measurements (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>9955567 - Disclosure - Fair Value Measurements (Fair Value of Financial Assets and Liabilities) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/FairValueMeasurementsFairValueofFinancialAssetsandLiabilitiesDetails1</Role>
      <ShortName>Fair Value Measurements (Fair Value of Financial Assets and Liabilities) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>9955568 - Disclosure - Fair Value Measurements (Reconciliation of Changes in Financial Liabilities Fair Value Using Level 3 Inputs) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/FairValueMeasurementsReconciliationofChangesinFinancialLiabilitiesFairValueUsingLevel3InputsDetails2</Role>
      <ShortName>Fair Value Measurements (Reconciliation of Changes in Financial Liabilities Fair Value Using Level 3 Inputs) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>9955569 - Disclosure - Revenue from Contracts with Customers (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractswithCustomersNarrativeDetails</Role>
      <ShortName>Revenue from Contracts with Customers (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/RevenuefromContractswithCustomersTables</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>9955570 - Disclosure - Revenue from Contract with Customer (Narrative 2) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractwithCustomerNarrative2Details</Role>
      <ShortName>Revenue from Contract with Customer (Narrative 2) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>9955571 - Disclosure - Revenue from Contracts with Customers (Contract Liability) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractswithCustomersContractLiabilityDetails</Role>
      <ShortName>Revenue from Contracts with Customers (Contract Liability) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/RevenuefromContractswithCustomersTables</ParentRole>
      <Position>90</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>9955572 - Disclosure - Revenue from Contracts with Customers (Capitalized Contract Cost) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/RevenuefromContractswithCustomersCapitalizedContractCostDetails</Role>
      <ShortName>Revenue from Contracts with Customers (Capitalized Contract Cost) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/RevenuefromContractswithCustomersTables</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>9955573 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsNarrativeDetails</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>9955574 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Stock Awards Rollforward) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsStockAwardsRollforwardDetails1</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Stock Awards Rollforward) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>93</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>9955575 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Stock Options Rollforward) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsStockOptionsRollforwardDetails2</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Stock Options Rollforward) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>94</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>9955576 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Options Outstanding and Exercisable) (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsOptionsOutstandingandExercisableDetails3</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Options Outstanding and Exercisable) (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>95</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>9955577 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Earnings Per Share) (Details 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsEarningsPerShareDetails5</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Earnings Per Share) (Details 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>96</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>9955578 - Disclosure - Capital Stock, Stock Awards, and Stock Options (Antidilutive Shares) (Details 6)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptionsAntidilutiveSharesDetails6</Role>
      <ShortName>Capital Stock, Stock Awards, and Stock Options (Antidilutive Shares) (Details 6)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/CapitalStockStockAwardsandStockOptions</ParentRole>
      <Position>97</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>9955579 - Disclosure - Pensions and Other Postretirement Plans (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansNarrativeDetails</Role>
      <ShortName>Pensions and Other Postretirement Plans (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>9955580 - Disclosure - Pensions and Other Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansObligationAssetandFundingInformationDetails1</Role>
      <ShortName>Pensions and Other Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>99</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>9955581 - Disclosure - Pensions and Other Postretirement Plans (Consolidated Balance Sheet) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansConsolidatedBalanceSheetDetails2</Role>
      <ShortName>Pensions and Other Postretirement Plans (Consolidated Balance Sheet) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>100</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>9955582 - Disclosure - Pensions and Other Postretirement Plans (Key Assumptions - Obligation) (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansKeyAssumptionsObligationDetails3</Role>
      <ShortName>Pensions and Other Postretirement Plans (Key Assumptions - Obligation) (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>101</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>9955583 - Disclosure - Pensions and Other Postretirement Plans (Future Estimated Benefit Payments) (Details 4)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansFutureEstimatedBenefitPaymentsDetails4</Role>
      <ShortName>Pensions and Other Postretirement Plans (Future Estimated Benefit Payments) (Details 4)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>102</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>9955584 - Disclosure - Pensions and Other Postretirement Plans (Total Benefit/Cost) (Details 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTotalBenefitCostDetails5</Role>
      <ShortName>Pensions and Other Postretirement Plans (Total Benefit/Cost) (Details 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>103</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>9955585 - Disclosure - Pensions and Other Postretirement Plans (Key Assumptions - Cost) (Details 6)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansKeyAssumptionsCostDetails6</Role>
      <ShortName>Pensions and Other Postretirement Plans (Key Assumptions - Cost) (Details 6)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>104</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>9955586 - Disclosure - Pensions and Other Postretirement Plans (Accumulated Other Comprehensive Income) (Details 7)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansAccumulatedOtherComprehensiveIncomeDetails7</Role>
      <ShortName>Pensions and Other Postretirement Plans (Accumulated Other Comprehensive Income) (Details 7)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>105</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>9955587 - Disclosure - Pensions and Other Postretirement Plans (Asset Allocation) (Details 8)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansAssetAllocationDetails8</Role>
      <ShortName>Pensions and Other Postretirement Plans (Asset Allocation) (Details 8)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>106</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>9955588 - Disclosure - Pensions and Other Postretirement Plans (Fair Value of Pension Plan Assets) (Details 9)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/PensionsandOtherPostretirementPlansFairValueofPensionPlanAssetsDetails9</Role>
      <ShortName>Pensions and Other Postretirement Plans (Fair Value of Pension Plan Assets) (Details 9)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/PensionsandOtherPostretirementPlansTables</ParentRole>
      <Position>107</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>9955589 - Disclosure - Other Non-Operating (Expense) Income (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OtherNonOperatingExpenseIncomeNarrativeDetails</Role>
      <ShortName>Other Non-Operating (Expense) Income (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/OtherNonOperatingExpenseIncomeTables</ParentRole>
      <Position>108</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>9955590 - Disclosure - Other Non-Operating (Expense) Income (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/OtherNonOperatingExpenseIncomeDetails1</Role>
      <ShortName>Other Non-Operating (Expense) Income (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/OtherNonOperatingExpenseIncomeTables</ParentRole>
      <Position>109</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>9955591 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossComponentsofOCIDetails1</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>110</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>9955592 - Disclosure - Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossAOCIbalancesDetails2</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>111</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>9955593 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossReclassificationsoutofAOCIDetails3</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/AccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>9955594 - Disclosure - Contingencies and Other Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/ContingenciesandOtherCommitmentsDetails</Role>
      <ShortName>Contingencies and Other Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/ContingenciesandOtherCommitments</ParentRole>
      <Position>113</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>9955595 - Disclosure - Business Segments (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/BusinessSegmentsNarrativeDetails</Role>
      <ShortName>Business Segments (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/BusinessSegmentsTables</ParentRole>
      <Position>114</Position>
    </Report>
    <Report instance="ghc-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>9955596 - Disclosure - Business Segments (Information by Operating Segment) (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ghco.com/role/BusinessSegmentsInformationbyOperatingSegmentDetails1</Role>
      <ShortName>Business Segments (Information by Operating Segment) (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ghco.com/role/BusinessSegmentsTables</ParentRole>
      <Position>115</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-K" isDefinitelyFs="true" isUsgaap="true" original="ghc-20251231.htm">ghc-20251231.htm</File>
    <File>ghc-20251231.xsd</File>
    <File>ghc-20251231_cal.xml</File>
    <File>ghc-20251231_def.xml</File>
    <File>ghc-20251231_lab.xml</File>
    <File>ghc-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>ghc-20251231_g1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="2704">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="39">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="5">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
