<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>126</ContextCount>
  <ElementCount>258</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>36</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Condensed Consolidated Statements of Financial Condition (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfFinancialConditionUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Financial Condition (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Condensed Consolidated Statements of Financial Condition (Parenthetical) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfFinancialConditionParentheticalUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Financial Condition (Parenthetical) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Condensed Consolidated Statements of Operations (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfOperationsUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Operations (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Condensed Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfComprehensiveIncomeUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Condensed Consolidated Statements of Changes in Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfChangesInEquityUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Changes in Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Condensed Consolidated Statements of Changes in Equity (Parenthetical) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfChangesInEquityParentheticalUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Changes in Equity (Parenthetical) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>75070 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_StatementCondensedConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.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>9</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.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>10</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Organization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureOrganization</Role>
      <ShortName>Organization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Revenues and Accounts Receivable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureRevenuesAndAccountsReceivable</Role>
      <ShortName>Revenues and Accounts Receivable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIntangibleAssets</Role>
      <ShortName>Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Furniture, Equipment and Leasehold Improvements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFurnitureEquipmentAndLeaseholdImprovements</Role>
      <ShortName>Furniture, Equipment and Leasehold Improvements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Net Income Per Share of Class A Common Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureNetIncomePerShareOfClassACommonStock</Role>
      <ShortName>Net Income Per Share of Class A Common Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Equity-Based and Other Deferred Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensation</Role>
      <ShortName>Equity-Based and Other Deferred Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Transactions With Related Parties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureTransactionsWithRelatedParties</Role>
      <ShortName>Transactions With Related Parties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Regulated Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureRegulatedEntities</Role>
      <ShortName>Regulated Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Segment and Geographic Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureSegmentAndGeographicInformation1</Role>
      <ShortName>Segment and Geographic Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Revenues and Accounts Receivable (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureRevenuesAndAccountsReceivableTables</Role>
      <ShortName>Revenues and Accounts Receivable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureRevenuesAndAccountsReceivable</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIntangibleAssetsTables</Role>
      <ShortName>Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIntangibleAssets</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Furniture, Equipment and Leasehold Improvements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFurnitureEquipmentAndLeaseholdImprovementsTables</Role>
      <ShortName>Furniture, Equipment and Leasehold Improvements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFurnitureEquipmentAndLeaseholdImprovements</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFairValueMeasurements</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxes</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Net Income Per Share of Class A Common Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureNetIncomePerShareOfClassACommonStockTables</Role>
      <ShortName>Net Income Per Share of Class A Common Stock (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureNetIncomePerShareOfClassACommonStock</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Equity-Based and Other Deferred Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationTables</Role>
      <ShortName>Equity-Based and Other Deferred Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureLeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureLeases</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Segment and Geographic Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureSegmentAndGeographicInformationTables</Role>
      <ShortName>Segment and Geographic Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureSegmentAndGeographicInformation1</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Organization - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureOrganizationAdditionalInformationDetails</Role>
      <ShortName>Organization - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Revenues and Accounts Receivable - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureRevenuesAndAccountsReceivableAdditionalInformationDetails</Role>
      <ShortName>Revenues and Accounts Receivable - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Revenues and Accounts Receivable - Schedule of Changes in the Allowance for Credit Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureRevenuesAndAccountsReceivableScheduleOfChangesInTheAllowanceForCreditLossesDetails</Role>
      <ShortName>Revenues and Accounts Receivable - Schedule of Changes in the Allowance for Credit Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Intangible Assets - Schedule of Intangible Assets, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIntangibleAssetsScheduleOfIntangibleAssetsNetDetails</Role>
      <ShortName>Intangible Assets - Schedule of Intangible Assets, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Intangible Assets - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIntangibleAssetsAdditionalInformationDetails</Role>
      <ShortName>Intangible Assets - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Furniture, Equipment and Leasehold Improvements - Schedule of Furniture, Equipment and Leasehold Improvements, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFurnitureEquipmentAndLeaseholdImprovementsScheduleOfFurnitureEquipmentAndLeaseholdImprovementsNetDetails</Role>
      <ShortName>Furniture, Equipment and Leasehold Improvements - Schedule of Furniture, Equipment and Leasehold Improvements, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Furniture, Equipment and Leasehold Improvements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFurnitureEquipmentAndLeaseholdImprovementsAdditionalInformationDetails</Role>
      <ShortName>Furniture, Equipment and Leasehold Improvements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Fair Value Measurements - Summary of Valuation of the Company's Investments by Fair Value Hierarchy (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureFairValueMeasurementsSummaryOfValuationOfCompanySInvestmentsByFairValueHierarchyDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Valuation of the Company's Investments by Fair Value Hierarchy (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Income Taxes - Summary of Company's Tax Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxesSummaryOfCompanySTaxPositionDetails</Role>
      <ShortName>Income Taxes - Summary of Company's Tax Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Income Taxes - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetails</Role>
      <ShortName>Income Taxes - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995825 - Disclosure - Net Income Per Share of Class A Common Stock - Schedule of Net Income Per Share of Class A Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureNetIncomePerShareOfClassACommonStockScheduleOfNetIncomePerShareOfClassACommonStockDetails</Role>
      <ShortName>Net Income Per Share of Class A Common Stock - Schedule of Net Income Per Share of Class A Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Net Income Per Share of Class A Common Stock - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureNetIncomePerShareOfClassACommonStockAdditionalInformationDetails</Role>
      <ShortName>Net Income Per Share of Class A Common Stock - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Equity-Based and Other Deferred Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationAdditionalInformationDetails</Role>
      <ShortName>Equity-Based and Other Deferred Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Equity-Based and Other Deferred Compensation - Stock-Based Compensation Expense and Related Income Tax Benefit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationStockBasedCompensationExpenseAndRelatedIncomeTaxBenefitDetails</Role>
      <ShortName>Equity-Based and Other Deferred Compensation - Stock-Based Compensation Expense and Related Income Tax Benefit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Equity-Based and Other Deferred Compensation - Summary of Activity Related to Unvested Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationSummaryOfActivityRelatedToUnvestedRestrictedStockUnitsDetails</Role>
      <ShortName>Equity-Based and Other Deferred Compensation - Summary of Activity Related to Unvested Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Equity-Based and Other Deferred Compensation - Summary of Activity Related to Unvested Partnership Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationSummaryOfActivityRelatedToUnvestedPartnershipUnitsDetails</Role>
      <ShortName>Equity-Based and Other Deferred Compensation - Summary of Activity Related to Unvested Partnership Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Equity-Based and Other Deferred Compensation - Unvested Units After Expected Forfeitures which are Expected to Vest (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureEquityBasedAndOtherDeferredCompensationUnvestedUnitsAfterExpectedForfeituresWhichAreExpectedToVestDetails</Role>
      <ShortName>Equity-Based and Other Deferred Compensation - Unvested Units After Expected Forfeitures which are Expected to Vest (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Leases - Schedule of Components of Lease Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureLeasesScheduleOfComponentsOfLeaseExpenseDetails</Role>
      <ShortName>Leases - Schedule of Components of Lease Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Leases - Schedule of Supplemental Information Related to Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureLeasesScheduleOfSupplementalInformationRelatedToLeasesDetails</Role>
      <ShortName>Leases - Schedule of Supplemental Information Related to Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Leases - Schedule of Maturity Analysis of Operating Lease Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureLeasesScheduleOfMaturityAnalysisOfOperatingLeaseLiabilitiesDetails</Role>
      <ShortName>Leases - Schedule of Maturity Analysis of Operating Lease Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Transactions With Related Parties - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureTransactionsWithRelatedPartiesAdditionalInformationDetails</Role>
      <ShortName>Transactions With Related Parties - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Regulated Entities - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureRegulatedEntitiesAdditionalInformationDetails</Role>
      <ShortName>Regulated Entities - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Segment and Geographic Information - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureSegmentAndGeographicInformationAdditionalInformationDetails</Role>
      <ShortName>Segment and Geographic Information - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Segment and Geographic Information - Schedule of Geographical Distribution of Revenues and Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/DisclosureSegmentAndGeographicInformationScheduleOfGeographicalDistributionOfRevenuesAndAssetsDetails</Role>
      <ShortName>Segment and Geographic Information - Schedule of Geographical Distribution of Revenues and Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="pjt-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pjtpartners.com/20260331/taxonomy/role/Role_DisclosureSubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</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-Q" isDefinitelyFs="true" isUsgaap="true" original="pjt-20260331.htm">pjt-20260331.htm</File>
    <File>pjt-20260331.xsd</File>
  </InputFiles>
  <SupplementalFiles>
    <File>img7618889_0.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="3">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="477">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="30">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
