<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>289</ContextCount>
  <ElementCount>518</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>98</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Consolidated Statements of Operations and Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConsolidatedStatementsOfOperationsAndComprehensiveLoss</Role>
      <ShortName>Consolidated Statements of Operations and Comprehensive Loss</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75050 - Statement - Consolidated Statements of Operations and Comprehensive Loss (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConsolidatedStatementsOfOperationsAndComprehensiveLossParenthetical</Role>
      <ShortName>Consolidated Statements of Operations and Comprehensive Loss (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75060 - Statement - Consolidated Statements of Changes in Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StatementConsolidatedStatementsOfChangesInStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75070 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StatementConsolidatedStatementsOfChangesInStockholdersEquityParenthetical</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>75080 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>75090 - Disclosure - Cybersecurity Risk Management, Strategy, and Governance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureCybersecurityRiskManagementStrategyAndGovernance</Role>
      <ShortName>Cybersecurity Risk Management, Strategy, and Governance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.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>11</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.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>12</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995457 - Disclosure - Organization and Background</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/OrganizationAndBackground</Role>
      <ShortName>Organization and Background</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995467 - Disclosure - Basis of Presentation and Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies1</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995477 - Disclosure - Property and Equipment, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/PropertyAndEquipmentNet</Role>
      <ShortName>Property and Equipment, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995487 - Disclosure - Website and Software Development Costs, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/WebsiteAndSoftwareDevelopmentCostsNet</Role>
      <ShortName>Website and Software Development Costs, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995497 - Disclosure - Intangible Assets, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IntangibleAssetsNet</Role>
      <ShortName>Intangible Assets, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995507 - Disclosure - Goodwill</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/Goodwill</Role>
      <ShortName>Goodwill</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995517 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/Acquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995527 - Disclosure - Acquisition-Related Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureAcquisitionrelatedLiabilities</Role>
      <ShortName>Acquisition-Related Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995537 - Disclosure - Accrued expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/AccruedExpenses</Role>
      <ShortName>Accrued expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995547 - Disclosure - Concentration of Credit Risk</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConcentrationOfCreditRisk</Role>
      <ShortName>Concentration of Credit Risk</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995557 - Disclosure - Credit Facilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilities</Role>
      <ShortName>Credit Facilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995567 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995577 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995587 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995597 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995617 - Disclosure - Fair Value Disclosures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/FairValueDisclosures</Role>
      <ShortName>Fair Value Disclosures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995637 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995647 - Disclosure - 401(k) Defined Contribution Plan</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/KDefinedContributionPlan</Role>
      <ShortName>401(k) Defined Contribution Plan</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995657 - Disclosure - Net Loss Per Share Attributable to Common Stockholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholders</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995667 - Disclosure - Other Expenses / (Income)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureOtherExpensesIncome</Role>
      <ShortName>Other Expenses / (Income)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995687 - Disclosure - Basis of Presentation and Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies1</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995697 - Disclosure - Basis of Presentation and Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesTables</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies1</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995707 - Disclosure - Property and Equipment, Net  (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/PropertyAndEquipmentNetTables</Role>
      <ShortName>Property and Equipment, Net  (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/PropertyAndEquipmentNet</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995717 - Disclosure - Website and Software Development Costs, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/WebsiteAndSoftwareDevelopmentCostsNetTables</Role>
      <ShortName>Website and Software Development Costs, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/WebsiteAndSoftwareDevelopmentCostsNet</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995727 - Disclosure - Intangible Assets, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IntangibleAssetsNetTables</Role>
      <ShortName>Intangible Assets, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IntangibleAssetsNet</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995737 - Disclosure - Goodwill (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/GoodwillTables</Role>
      <ShortName>Goodwill (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/Goodwill</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995747 - Disclosure - Acquisition-Related Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureAcquisitionrelatedLiabilitiesTables</Role>
      <ShortName>Acquisition-Related Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureAcquisitionrelatedLiabilities</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995757 - Disclosure - Accrued expenses  - (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/AccruedExpensesTables</Role>
      <ShortName>Accrued expenses  - (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/AccruedExpenses</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995767 - Disclosure - Credit Facilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilitiesTables</Role>
      <ShortName>Credit Facilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilities</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995777 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CommitmentsAndContingencies</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995787 - Disclosure - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StockBasedCompensationTables</Role>
      <ShortName>Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StockBasedCompensation</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995807 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeases</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995827 - Disclosure - Fair Value Disclosures (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/FairValueDisclosuresTables</Role>
      <ShortName>Fair Value Disclosures (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/FairValueDisclosures</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995837 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IncomeTaxes</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995847 - Disclosure - Net Loss Per Share Attributable to Common Stockholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholdersTables</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholders</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995857 - Disclosure - Other Expenses / (Income) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureOtherExpensesIncomeTables</Role>
      <ShortName>Other Expenses / (Income) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureOtherExpensesIncome</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995887 - Disclosure - Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995897 - Disclosure - Basis of Presentation and Significant Accounting Policies - Additional Information 1 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesAdditionalInformation1Details</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Additional Information 1 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995907 - Disclosure - Basis of Presentation and Significant Accounting Policies - Summary of Disaggregation of Revenue (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesSummaryOfDisaggregationOfRevenueDetail</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Summary of Disaggregation of Revenue (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995917 - Disclosure - Basis of Presentation and Significant Accounting Policies - Schedule of Changes in the Allowance for Doubtful Accounts (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesScheduleOfChangesInTheAllowanceForDoubtfulAccountsDetail</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Schedule of Changes in the Allowance for Doubtful Accounts (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995927 - Disclosure - Basis of Presentation and Significant Accounting Policies - Schedule of Estimated Useful Lives of Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesScheduleOfEstimatedUsefulLivesOfAssetsDetail</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Schedule of Estimated Useful Lives of Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995937 - Disclosure - Basis of Presentation and Significant Accounting Policies - Schedule of Weighted Average Useful Lives of Intangible Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesScheduleOfWeightedAverageUsefulLivesOfIntangibleAssetsDetail</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Schedule of Weighted Average Useful Lives of Intangible Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995947 - Disclosure - Basis of Presentation and Significant Accounting Policies - Schedule of Revenues and Long-lived Assets by Geographic Region are Based on the Physical Location of the Customers Being Served or the Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesScheduleOfRevenuesAndLonglivedAssetsByGeographicRegionAreBasedOnThePhysical</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies - Schedule of Revenues and Long-lived Assets by Geographic Region are Based on the Physical Location of the Customers Being Served or the Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995957 - Disclosure - Property and Equipment, Net  - Summary of Property and Equipment, Net and Related Accumulated Depreciation (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetAndRelatedAccumulatedDepreciationDetail</Role>
      <ShortName>Property and Equipment, Net  - Summary of Property and Equipment, Net and Related Accumulated Depreciation (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995967 - Disclosure - Property and Equipment, Net  - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/PropertyAndEquipmentNetAdditionalInformationDetail</Role>
      <ShortName>Property and Equipment, Net  - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995977 - Disclosure - Website and Software Development Costs, Net - Summary of Website and Software Development Costs (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/WebsiteAndSoftwareDevelopmentCostsNetSummaryOfWebsiteAndSoftwareDevelopmentCostsDetail</Role>
      <ShortName>Website and Software Development Costs, Net - Summary of Website and Software Development Costs (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995987 - Disclosure - Website and Software Development Costs, Net - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/WebsiteAndSoftwareDevelopmentCostsNetAdditionalInformationDetail</Role>
      <ShortName>Website and Software Development Costs, Net - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995997 - Disclosure - Intangible Assets, Net - Summary of Intangible Assets and Related Accumulated Amortization (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIntangibleAssetsNetSummaryOfIntangibleAssetsAndRelatedAccumulatedAmortizationDetail</Role>
      <ShortName>Intangible Assets, Net - Summary of Intangible Assets and Related Accumulated Amortization (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>996007 - Disclosure - Intangible Assets, Net - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIntangibleAssetsNetAdditionalInformationDetail</Role>
      <ShortName>Intangible Assets, Net - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>996017 - Disclosure - Intangible Assets, Net - Summary of Total Estimated Future Amortization (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIntangibleAssetsNetSummaryOfTotalEstimatedFutureAmortizationDetail</Role>
      <ShortName>Intangible Assets, Net - Summary of Total Estimated Future Amortization (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>996027 - Disclosure - Goodwill - Summary of Goodwill (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/GoodwillSummaryOfGoodwillDetail</Role>
      <ShortName>Goodwill - Summary of Goodwill (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>996037 - Disclosure - Goodwill - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureGoodwillAdditionalInformationDetail</Role>
      <ShortName>Goodwill - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>996047 - Disclosure - Acquisitions - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/AcquisitionsAdditionalInformationDetail</Role>
      <ShortName>Acquisitions - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>996057 - Disclosure - Acquisition-Related Liabilities - Schedule of Acquisition Related Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureAcquisitionrelatedLiabilitiesScheduleOfAcquisitionRelatedLiabilitiesDetail</Role>
      <ShortName>Acquisition-Related Liabilities - Schedule of Acquisition Related Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>996077 - Disclosure - Accrued expenses - Summary of Accrued Expenses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureAccruedExpensesSummaryOfAccruedExpensesDetail</Role>
      <ShortName>Accrued expenses - Summary of Accrued Expenses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>996087 - Disclosure - Concentration of Credit Risk - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/ConcentrationOfCreditRiskAdditionalInformationDetail</Role>
      <ShortName>Concentration of Credit Risk - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>996097 - Disclosure - Credit Facilities - Summary of Long-Term Borrowings (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilitiesSummaryOfLongTermBorrowingsDetail</Role>
      <ShortName>Credit Facilities - Summary of Long-Term Borrowings (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>996107 - Disclosure - Credit Facilities - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilitiesAdditionalInformationDetail</Role>
      <ShortName>Credit Facilities - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>996117 - Disclosure - Credit Facilities - Summary of Maturities of Long-term Debt (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilitiesSummaryOfMaturitiesOfLongTermDebtDetail</Role>
      <ShortName>Credit Facilities - Summary of Maturities of Long-term Debt (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>996127 - Disclosure - Credit Facilities - Summary of Maturities of Long-term Debt (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CreditFacilitiesSummaryOfMaturitiesOfLongTermDebtParentheticalDetail</Role>
      <ShortName>Credit Facilities - Summary of Maturities of Long-term Debt (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>996147 - Disclosure - Commitments and Contingencies - Summary of Long-term Purchase Commitment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/CommitmentsAndContingenciesSummaryOfLongTermPurchaseCommitmentDetail</Role>
      <ShortName>Commitments and Contingencies - Summary of Long-term Purchase Commitment (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>996157 - Disclosure - Stock-Based Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StockBasedCompensationAdditionalInformationDetail</Role>
      <ShortName>Stock-Based Compensation - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>996167 - Disclosure - Stock-Based Compensation - Summary of Activity of Restricted Stock And Restricted Stock Units Granted By Company (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfActivityOfRestrictedStockAndRestrictedStockUnitsGrantedByCompanyDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Activity of Restricted Stock And Restricted Stock Units Granted By Company (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>996177 - Disclosure - Stock-Based Compensation - Summary of Activity of Restricted Stock And Restricted Stock Units Granted By Company (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfActivityOfRestrictedStockAndRestrictedStockUnitsGrantedByCompanyParentheticalDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Activity of Restricted Stock And Restricted Stock Units Granted By Company (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>996187 - Disclosure - Stock-Based Compensation - Summary of Transaction under Plans and 2021 Plan (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfTransactionUnderPlansAnd2021PlanDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Transaction under Plans and 2021 Plan (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>996197 - Disclosure - Stock-Based Compensation - Share Based Compensation Performance Shares Award Valuation Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockbasedCompensationShareBasedCompensationPerformanceSharesAwardValuationAssumptionsDetails</Role>
      <ShortName>Stock-Based Compensation - Share Based Compensation Performance Shares Award Valuation Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>996217 - Disclosure - Stock-Based Compensation - Schedule Of Share Based Payment Award Employee Stock Purchase Plan Valuation Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/StockBasedCompensationScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsDetails</Role>
      <ShortName>Stock-Based Compensation - Schedule Of Share Based Payment Award Employee Stock Purchase Plan Valuation Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>996227 - Disclosure - Stockholders' Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetail</Role>
      <ShortName>Stockholders' Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>996267 - Disclosure - Leases - Summary of Right-of-Use Asset and Lease Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeasesSummaryOfRightofuseAssetAndLeaseLiabilitiesDetail</Role>
      <ShortName>Leases - Summary of Right-of-Use Asset and Lease Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>996277 - Disclosure - Leases - Schedule of Supplemental Information Related to Operating Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeasesScheduleOfSupplementalInformationRelatedToOperatingLeasesDetail</Role>
      <ShortName>Leases - Schedule of Supplemental Information Related to Operating Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>996287 - Disclosure - Leases - Summary of Future Minimum Payments Under Operating Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureLeasesSummaryOfFutureMinimumPaymentsUnderOperatingLeasesDetail3</Role>
      <ShortName>Leases - Summary of Future Minimum Payments Under Operating Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>996327 - Disclosure - Fair Value Disclosures - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureFairValueDisclosuresAdditionalInformationDetails</Role>
      <ShortName>Fair Value Disclosures - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>996337 - Disclosure - Fair Value Disclosures - Summary of Financial Instruments Measured At Fair Value On a Recurring Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/FairValueDisclosuresSummaryOfFinancialInstrumentsMeasuredAtFairValueOnARecurringBasisDetail</Role>
      <ShortName>Fair Value Disclosures - Summary of Financial Instruments Measured At Fair Value On a Recurring Basis (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>996347 - Disclosure - Fair Value Disclosures - Summary of Reconciliations of Changes In The Fair Value of The Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/FairValueDisclosuresSummaryOfReconciliationsOfChangesInTheFairValueOfTheLiabilitiesDetail</Role>
      <ShortName>Fair Value Disclosures - Summary of Reconciliations of Changes In The Fair Value of The Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>996357 - Disclosure - Related Party Transactions - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/RelatedPartyTransactionsAdditionalInformationDetail</Role>
      <ShortName>Related Party Transactions - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>996367 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IncomeTaxesAdditionalInformationDetail</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>996377 - Disclosure - Income Taxes - Schedule of Income Before Income Tax Domestic And Foreign (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignDetail</Role>
      <ShortName>Income Taxes - Schedule of Income Before Income Tax Domestic And Foreign (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>996387 - Disclosure - Income Taxes - Schedule of Components of Income Tax Expense Benefit (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesScheduleOfComponentsOfIncomeTaxExpenseBenefitDetail</Role>
      <ShortName>Income Taxes - Schedule of Components of Income Tax Expense Benefit (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>996397 - Disclosure - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationDetail</Role>
      <ShortName>Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>996407 - Disclosure - Income Taxes - Schedule of Deferred Tax Assets And Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesScheduleOfDeferredTaxAssetsAndLiabilitiesDetail</Role>
      <ShortName>Income Taxes - Schedule of Deferred Tax Assets And Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>996427 - Disclosure - Income Taxes - Summary of Income Tax Contingencies (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesSummaryOfIncomeTaxContingenciesDetail</Role>
      <ShortName>Income Taxes - Summary of Income Tax Contingencies (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>996437 - Disclosure - Income Taxes - Schedule of Cash Income Taxes Paid (Net of Refunds) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureIncomeTaxesScheduleOfCashIncomeTaxesPaidNetOfRefundsDetail</Role>
      <ShortName>Income Taxes - Schedule of Cash Income Taxes Paid (Net of Refunds) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>996447 - Disclosure - Income Taxes -Income Tax Years Subject To Examination (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/IncomeTaxesIncomeTaxYearsSubjectToExaminationDetail</Role>
      <ShortName>Income Taxes -Income Tax Years Subject To Examination (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>996457 - Disclosure - 401(k) Defined Contribution Plan - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/KDefinedContributionPlanAdditionalInformationDetail</Role>
      <ShortName>401(k) Defined Contribution Plan - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>996467 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholdersAdditionalInformationDetail</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>996477 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Summary of Basic and Diluted Net Loss Per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholdersSummaryOfBasicAndDilutedNetLossPerShareDetail</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders - Summary of Basic and Diluted Net Loss Per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>996487 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Schedule of Anti-Dilutive Common Equivalent Shares (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/NetLossPerShareAttributableToCommonStockholdersScheduleOfAntiDilutiveCommonEquivalentSharesDetail</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders - Schedule of Anti-Dilutive Common Equivalent Shares (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="zeta-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>996497 - Disclosure - Other Expenses / (Income) - Schedule of Other Operating Cost and Expense (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureOtherExpensesIncomeScheduleOfOtherOperatingCostAndExpenseDetail</Role>
      <ShortName>Other Expenses / (Income) - Schedule of Other Operating Cost and Expense (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.zetaglobalholdingscorp.com/20251231/taxonomy/role/DisclosureOtherExpensesIncomeTables</ParentRole>
      <Position>100</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="zeta-20251231.htm">zeta-20251231.htm</File>
    <File>zeta-20251231.xsd</File>
  </InputFiles>
  <SupplementalFiles>
    <File>img234239880_0.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="2">http://fasb.org/srt/2024</BaseTaxonomy>
    <BaseTaxonomy items="1016">http://fasb.org/us-gaap/2024</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2024</BaseTaxonomy>
    <BaseTaxonomy items="41">http://xbrl.sec.gov/dei/2024</BaseTaxonomy>
    <BaseTaxonomy items="5">http://xbrl.sec.gov/ecd/2024</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
