<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>323</ContextCount>
  <ElementCount>501</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>102</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Document - Audit Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AuditInformation</Role>
      <ShortName>Audit Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ConsolidatedStatementsofOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Statements of Stockholders??? Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ConsolidatedStatementsofStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Stockholders??? Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="comp-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://compassinc.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952156 - Disclosure - Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/Business</Role>
      <ShortName>Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/Acquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Equity Method Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/EquityMethodInvestments</Role>
      <ShortName>Equity Method Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Fair Value of Financial Assets and Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/FairValueofFinancialAssetsandLiabilities</Role>
      <ShortName>Fair Value of Financial Assets and Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Property and Equipment, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PropertyandEquipmentNet</Role>
      <ShortName>Property and Equipment, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Goodwill and Intangible Assets, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNet</Role>
      <ShortName>Goodwill and Intangible Assets, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Accrued Expenses and Other Current Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AccruedExpensesandOtherCurrentLiabilities</Role>
      <ShortName>Accrued Expenses and Other Current Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Preferred Stock and Common Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PreferredStockandCommonStock</Role>
      <ShortName>Preferred Stock and Common Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Compass Concierge Receivables and Allowance for Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLosses</Role>
      <ShortName>Compass Concierge Receivables and Allowance for Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - Net Loss Per Share Attributable to Compass, Inc.</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/NetLossPerShareAttributabletoCompassInc</Role>
      <ShortName>Net Loss Per Share Attributable to Compass, Inc.</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - Restructuring Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivities</Role>
      <ShortName>Restructuring Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9952174 - Disclosure - Schedule II. Valuation and Qualifying Accounts</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ScheduleIIValuationandQualifyingAccounts</Role>
      <ShortName>Schedule II. Valuation and Qualifying Accounts</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.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>27</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.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>28</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.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>29</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://compassinc.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsTables</Role>
      <ShortName>Acquisitions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/Acquisitions</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Fair Value of Financial Assets and Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/FairValueofFinancialAssetsandLiabilitiesTables</Role>
      <ShortName>Fair Value of Financial Assets and Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/FairValueofFinancialAssetsandLiabilities</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Property and Equipment, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PropertyandEquipmentNetTables</Role>
      <ShortName>Property and Equipment, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/PropertyandEquipmentNet</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Goodwill and Intangible Assets, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNetTables</Role>
      <ShortName>Goodwill and Intangible Assets, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/GoodwillandIntangibleAssetsNet</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Accrued Expenses and Other Current Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AccruedExpensesandOtherCurrentLiabilitiesTables</Role>
      <ShortName>Accrued Expenses and Other Current Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/AccruedExpensesandOtherCurrentLiabilities</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/Leases</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Preferred Stock and Common Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PreferredStockandCommonStockTables</Role>
      <ShortName>Preferred Stock and Common Stock (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/PreferredStockandCommonStock</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensationTables</Role>
      <ShortName>Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/StockBasedCompensation</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/IncomeTaxes</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Compass Concierge Receivables and Allowance for Credit Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLossesTables</Role>
      <ShortName>Compass Concierge Receivables and Allowance for Credit Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLosses</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Net Loss Per Share Attributable to Compass, Inc. (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/NetLossPerShareAttributabletoCompassIncTables</Role>
      <ShortName>Net Loss Per Share Attributable to Compass, Inc. (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/NetLossPerShareAttributabletoCompassInc</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Restructuring Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivitiesTables</Role>
      <ShortName>Restructuring Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://compassinc.com/role/RestructuringActivities</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Business (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/BusinessDetails</Role>
      <ShortName>Business (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/Business</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPoliciesAdditionalInformationDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Summary of Significant Accounting Policies - Schedule of Activity of the Allowance For Credit Losses For Accounts Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPoliciesScheduleofActivityoftheAllowanceForCreditLossesForAccountsReceivableDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Schedule of Activity of the Allowance For Credit Losses For Accounts Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - Summary of Significant Accounting Policies - Schedule of Useful Lives of Property and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SummaryofSignificantAccountingPoliciesScheduleofUsefulLivesofPropertyandEquipmentDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Schedule of Useful Lives of Property and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Acquisitions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsAdditionalInformationDetails</Role>
      <ShortName>Acquisitions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Acquisitions - Schedule of Individual Elements Within the Calculation of Total Consideration Transferred (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsScheduleofIndividualElementsWithintheCalculationofTotalConsiderationTransferredDetails</Role>
      <ShortName>Acquisitions - Schedule of Individual Elements Within the Calculation of Total Consideration Transferred (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Acquisitions - Schedule of Preliminary Allocation of Purchase Price to the Estimated Fair Values of Net Assets Acquired (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsScheduleofPreliminaryAllocationofPurchasePricetotheEstimatedFairValuesofNetAssetsAcquiredDetails</Role>
      <ShortName>Acquisitions - Schedule of Preliminary Allocation of Purchase Price to the Estimated Fair Values of Net Assets Acquired (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Acquisitions - Schedule of Fair Value of Identified Intangible Assets And Useful Lives at the Time of Acquisition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsScheduleofFairValueofIdentifiedIntangibleAssetsAndUsefulLivesattheTimeofAcquisitionDetails</Role>
      <ShortName>Acquisitions - Schedule of Fair Value of Identified Intangible Assets And Useful Lives at the Time of Acquisition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - Acquisitions - Schedule of Pro Forma Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsScheduleofProFormaInformationDetails</Role>
      <ShortName>Acquisitions - Schedule of Pro Forma Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Acquisitions - Schedule of Changes in Contingent Consideration Measured at Fair Value on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AcquisitionsScheduleofChangesinContingentConsiderationMeasuredatFairValueonaRecurringBasisDetails</Role>
      <ShortName>Acquisitions - Schedule of Changes in Contingent Consideration Measured at Fair Value on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Equity Method Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/EquityMethodInvestmentsDetails</Role>
      <ShortName>Equity Method Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/EquityMethodInvestments</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Fair Value of Financial Assets and Liabilities - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/FairValueofFinancialAssetsandLiabilitiesAdditionalInformationDetails</Role>
      <ShortName>Fair Value of Financial Assets and Liabilities - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Fair Value of Financial Assets and Liabilities - Schedule of Balances of Contingent Consideration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/FairValueofFinancialAssetsandLiabilitiesScheduleofBalancesofContingentConsiderationDetails</Role>
      <ShortName>Fair Value of Financial Assets and Liabilities - Schedule of Balances of Contingent Consideration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Property and Equipment, Net - Schedule of Property Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PropertyandEquipmentNetScheduleofPropertyPlantandEquipmentDetails</Role>
      <ShortName>Property and Equipment, Net - Schedule of Property Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Property and Equipment, Net - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PropertyandEquipmentNetAdditionalInformationDetails</Role>
      <ShortName>Property and Equipment, Net - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Goodwill and Intangible Assets, Net - Schedule of Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNetScheduleofGoodwillDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Schedule of Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Goodwill and Intangible Assets, Net - Schedule of Carrying Amounts and Accumulated Amortization of Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNetScheduleofCarryingAmountsandAccumulatedAmortizationofIntangibleAssetsDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Schedule of Carrying Amounts and Accumulated Amortization of Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Goodwill and Intangible Assets, Net - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNetAdditionalInformationDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Goodwill and Intangible Assets, Net - Schedule of Finite Lived Intangible Assets Future Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/GoodwillandIntangibleAssetsNetScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Schedule of Finite Lived Intangible Assets Future Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - Accrued Expenses and Other Current Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/AccruedExpensesandOtherCurrentLiabilitiesDetails</Role>
      <ShortName>Accrued Expenses and Other Current Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/AccruedExpensesandOtherCurrentLiabilitiesTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/DebtDetails</Role>
      <ShortName>Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/Debt</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - Leases - Schedule of Operating Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesScheduleofOperatingLeasesDetails</Role>
      <ShortName>Leases - Schedule of Operating Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - Leases - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesAdditionalInformationDetails</Role>
      <ShortName>Leases - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - Leases - Schedule of Supplemental Cash Flow Information Related To Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesScheduleofSupplementalCashFlowInformationRelatedToLeasesDetails</Role>
      <ShortName>Leases - Schedule of Supplemental Cash Flow Information Related To Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - Leases - Schedule of Weighted-average Remaining Lease Term and Discount Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesScheduleofWeightedaverageRemainingLeaseTermandDiscountRateDetails</Role>
      <ShortName>Leases - Schedule of Weighted-average Remaining Lease Term and Discount Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - Leases - Schedule of Operating Lease Liability Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/LeasesScheduleofOperatingLeaseLiabilityMaturityDetails</Role>
      <ShortName>Leases - Schedule of Operating Lease Liability Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>9955551 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/CommitmentsandContingencies</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>9955552 - Disclosure - Preferred Stock and Common Stock - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PreferredStockandCommonStockAdditionalInformationDetails</Role>
      <ShortName>Preferred Stock and Common Stock - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>9955553 - Disclosure - Preferred Stock and Common Stock - Schedule of Authorized, Issued and Outstanding Shares for Each Classes of Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/PreferredStockandCommonStockScheduleofAuthorizedIssuedandOutstandingSharesforEachClassesofCommonStockDetails</Role>
      <ShortName>Preferred Stock and Common Stock - Schedule of Authorized, Issued and Outstanding Shares for Each Classes of Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>9955554 - Disclosure - Stock-Based Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensationAdditionalInformationDetails</Role>
      <ShortName>Stock-Based Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>9955555 - Disclosure - Stock-Based Compensation - Schedule of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensationScheduleofStockOptionActivityDetails</Role>
      <ShortName>Stock-Based Compensation - Schedule of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>9955556 - Disclosure - Stock-Based Compensation - Schedule of Restricted Stock Units Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensationScheduleofRestrictedStockUnitsActivityDetails</Role>
      <ShortName>Stock-Based Compensation - Schedule of Restricted Stock Units Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>9955557 - Disclosure - Stock-Based Compensation - Schedule of Total Stock-Based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/StockBasedCompensationScheduleofTotalStockBasedCompensationExpenseDetails</Role>
      <ShortName>Stock-Based Compensation - Schedule of Total Stock-Based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>9955558 - Disclosure - Income Taxes - Schedule of Loss Before Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesScheduleofLossBeforeIncomeTaxesDetails</Role>
      <ShortName>Income Taxes - Schedule of Loss Before Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>9955559 - Disclosure - Income Taxes - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesAdditionalInformationDetails</Role>
      <ShortName>Income Taxes - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>9955560 - Disclosure - Income Taxes - Schedule of Components of Income Tax Benefit (Provision) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesScheduleofComponentsofIncomeTaxBenefitProvisionDetails</Role>
      <ShortName>Income Taxes - Schedule of Components of Income Tax Benefit (Provision) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>9955561 - Disclosure - Income Taxes - Schedule of Income Taxes Paid, Net of Refunds Received (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesScheduleofIncomeTaxesPaidNetofRefundsReceivedDetails</Role>
      <ShortName>Income Taxes - Schedule of Income Taxes Paid, Net of Refunds Received (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>9955562 - Disclosure - Income Taxes - Schedule of Effective Income Tax Rate Differed From the Statutory Federal Income Tax Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesScheduleofEffectiveIncomeTaxRateDifferedFromtheStatutoryFederalIncomeTaxRateDetails</Role>
      <ShortName>Income Taxes - Schedule of Effective Income Tax Rate Differed From the Statutory Federal Income Tax Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>9955563 - Disclosure - Income Taxes - Schedule of Components of Net Deferred Taxes Arising from Temporary Differences (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/IncomeTaxesScheduleofComponentsofNetDeferredTaxesArisingfromTemporaryDifferencesDetails</Role>
      <ShortName>Income Taxes - Schedule of Components of Net Deferred Taxes Arising from Temporary Differences (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>9955564 - Disclosure - Compass Concierge Receivables and Allowance for Credit Losses - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLossesAdditionalInformationDetails</Role>
      <ShortName>Compass Concierge Receivables and Allowance for Credit Losses - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>9955565 - Disclosure - Compass Concierge Receivables and Allowance for Credit Losses - Schedule of Activity of ACL for Concierge Receivables (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLossesScheduleofActivityofACLforConciergeReceivablesDetails</Role>
      <ShortName>Compass Concierge Receivables and Allowance for Credit Losses - Schedule of Activity of ACL for Concierge Receivables (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>9955566 - Disclosure - Compass Concierge Receivables and Allowance for Credit Losses - Schedule of Aging Analysis of Concierge Receivables (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/CompassConciergeReceivablesandAllowanceforCreditLossesScheduleofAgingAnalysisofConciergeReceivablesDetails</Role>
      <ShortName>Compass Concierge Receivables and Allowance for Credit Losses - Schedule of Aging Analysis of Concierge Receivables (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>9955567 - Disclosure - Net Loss Per Share Attributable to Compass, Inc. - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/NetLossPerShareAttributabletoCompassIncScheduleofComputationofBasicandDilutedNetLossPerShareAttributabletoCommonStockholdersDetails</Role>
      <ShortName>Net Loss Per Share Attributable to Compass, Inc. - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>9955568 - Disclosure - Net Loss Per Share Attributable to Compass, Inc. - Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/NetLossPerShareAttributabletoCompassIncScheduleofComputationofDilutedNetLossPerShareAttributabletoCommonStockholdersDetails</Role>
      <ShortName>Net Loss Per Share Attributable to Compass, Inc. - Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>9955569 - Disclosure - Restructuring Activities - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivitiesAdditionalInformationDetails</Role>
      <ShortName>Restructuring Activities - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>9955570 - Disclosure - Restructuring Activities - Schedule of Restructuring Costs Incurred (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivitiesScheduleofRestructuringCostsIncurredDetails</Role>
      <ShortName>Restructuring Activities - Schedule of Restructuring Costs Incurred (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>9955571 - Disclosure - Restructuring Activities - Schedule of Total Costs Incurred in Connection to Restructuring Activities Included in Statements of Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivitiesScheduleofTotalCostsIncurredinConnectiontoRestructuringActivitiesIncludedinStatementsofOperationsDetails</Role>
      <ShortName>Restructuring Activities - Schedule of Total Costs Incurred in Connection to Restructuring Activities Included in Statements of Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>9955572 - Disclosure - Restructuring Activities - Schedule of Remaining Liability For Lease Termination Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/RestructuringActivitiesScheduleofRemainingLiabilityForLeaseTerminationCostsDetails</Role>
      <ShortName>Restructuring Activities - Schedule of Remaining Liability For Lease Termination Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>9955573 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/SubsequentEvents</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="comp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>9955574 - Disclosure - Schedule II. Valuation and Qualifying Accounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://compassinc.com/role/ScheduleIIValuationandQualifyingAccountsDetails</Role>
      <ShortName>Schedule II. Valuation and Qualifying Accounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://compassinc.com/role/ScheduleIIValuationandQualifyingAccounts</ParentRole>
      <Position>93</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="comp-20251231.htm">comp-20251231.htm</File>
    <File>comp-20251231.xsd</File>
    <File>comp-20251231_cal.xml</File>
    <File>comp-20251231_def.xml</File>
    <File>comp-20251231_lab.xml</File>
    <File>comp-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>comp-20251231_g1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="1068">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="40">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>
