<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1291</ContextCount>
  <ElementCount>942</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>315</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>18</UnitCount>
  <MyReports>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/Cover</Role>
      <ShortName>Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Document - Audit Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/AuditInformation</Role>
      <ShortName>Audit Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Balance Sheets (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedBalanceSheetsParentheticals</Role>
      <ShortName>Consolidated Balance Sheets (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Statements of Operations (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofOperationsParenthetical</Role>
      <ShortName>Consolidated Statements of Operations (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952155 - Statement - Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofComprehensiveIncomeLoss</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952156 - Statement - Consolidated Statements of Equity (Deficit)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofEquityDeficit</Role>
      <ShortName>Consolidated Statements of Equity (Deficit)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952157 - Statement - Condensed Consolidated Statements of Equity (Deficit) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CondensedConsolidatedStatementsofEquityDeficitParenthetical</Role>
      <ShortName>Condensed Consolidated Statements of Equity (Deficit) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952158 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952159 - Statement - Consolidated Statements of Cash Flows (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ConsolidatedStatementsofCashFlowsParenthetical</Role>
      <ShortName>Consolidated Statements of Cash Flows (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - ORGANIZATION AND NATURE OF BUSINESS OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ORGANIZATIONANDNATUREOFBUSINESSOPERATIONS</Role>
      <ShortName>ORGANIZATION AND NATURE OF BUSINESS OPERATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - VARIABLE INTEREST ENTITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/VARIABLEINTERESTENTITIES</Role>
      <ShortName>VARIABLE INTEREST ENTITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - ACQUISITIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACQUISITIONS</Role>
      <ShortName>ACQUISITIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALE</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - FAIR VALUE MEASUREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTS</Role>
      <ShortName>FAIR VALUE MEASUREMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASED</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - SECURITIES LENDING</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESLENDING</Role>
      <ShortName>SECURITIES LENDING</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - ACCOUNTS RECEIVABLE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCOUNTSRECEIVABLE</Role>
      <ShortName>ACCOUNTS RECEIVABLE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - LOANS RECEIVABLE, AT FAIR VALUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LOANSRECEIVABLEATFAIRVALUE</Role>
      <ShortName>LOANS RECEIVABLE, AT FAIR VALUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - EQUITY METHOD INVESTMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTS</Role>
      <ShortName>EQUITY METHOD INVESTMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - PREPAID EXPENSES AND OTHER ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PREPAIDEXPENSESANDOTHERASSETS</Role>
      <ShortName>PREPAID EXPENSES AND OTHER ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - PROPERTY AND EQUIPMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PROPERTYANDEQUIPMENT</Role>
      <ShortName>PROPERTY AND EQUIPMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETS</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9952174 - Disclosure - ACCRUED EXPENSES AND OTHER LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCRUEDEXPENSESANDOTHERLIABILITIES</Role>
      <ShortName>ACCRUED EXPENSES AND OTHER LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9952175 - Disclosure - LEASING ARRANGEMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LEASINGARRANGEMENTS</Role>
      <ShortName>LEASING ARRANGEMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9952176 - Disclosure - NOTES PAYABLE</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/NOTESPAYABLE</Role>
      <ShortName>NOTES PAYABLE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9952177 - Disclosure - TERM LOANS AND REVOLVING CREDIT FACILITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/TERMLOANSANDREVOLVINGCREDITFACILITY</Role>
      <ShortName>TERM LOANS AND REVOLVING CREDIT FACILITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9952178 - Disclosure - SENIOR NOTES PAYABLE</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLE</Role>
      <ShortName>SENIOR NOTES PAYABLE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9952179 - Disclosure - NONCONTROLLING INTERESTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/NONCONTROLLINGINTERESTS</Role>
      <ShortName>NONCONTROLLING INTERESTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9952180 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERS</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9952181 - Disclosure - RESTRUCTURING CHARGE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RESTRUCTURINGCHARGE</Role>
      <ShortName>RESTRUCTURING CHARGE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9952182 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXES</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9952183 - Disclosure - EARNINGS PER SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EARNINGSPERSHARE</Role>
      <ShortName>EARNINGS PER SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9952184 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANS</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9952185 - Disclosure - STOCKHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITY</Role>
      <ShortName>STOCKHOLDERS' EQUITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9952186 - Disclosure - NET CAPITAL REQUIREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/NETCAPITALREQUIREMENTS</Role>
      <ShortName>NET CAPITAL REQUIREMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9952187 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RELATEDPARTYTRANSACTIONS</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9952188 - Disclosure - BUSINESS SEGMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTS</Role>
      <ShortName>BUSINESS SEGMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9952189 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/COMMITMENTSANDCONTINGENCIES</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9952190 - Disclosure - SUBSEQUENT EVENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUBSEQUENTEVENT</Role>
      <ShortName>SUBSEQUENT EVENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9952191 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformation</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.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>44</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.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>45</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - VARIABLE INTEREST ENTITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/VARIABLEINTERESTENTITIESTables</Role>
      <ShortName>VARIABLE INTEREST ENTITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/VARIABLEINTERESTENTITIES</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - ACQUISITIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACQUISITIONSTables</Role>
      <ShortName>ACQUISITIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/ACQUISITIONS</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALETables</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALE</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTS</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDTables</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASED</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - SECURITIES LENDING (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESLENDINGTables</Role>
      <ShortName>SECURITIES LENDING (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SECURITIESLENDING</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - ACCOUNTS RECEIVABLE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCOUNTSRECEIVABLETables</Role>
      <ShortName>ACCOUNTS RECEIVABLE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/ACCOUNTSRECEIVABLE</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - LOANS RECEIVABLE, AT FAIR VALUE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LOANSRECEIVABLEATFAIRVALUETables</Role>
      <ShortName>LOANS RECEIVABLE, AT FAIR VALUE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/LOANSRECEIVABLEATFAIRVALUE</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - EQUITY METHOD INVESTMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTSTables</Role>
      <ShortName>EQUITY METHOD INVESTMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTS</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - PREPAID EXPENSES AND OTHER ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PREPAIDEXPENSESANDOTHERASSETSTables</Role>
      <ShortName>PREPAID EXPENSES AND OTHER ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/PREPAIDEXPENSESANDOTHERASSETS</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - PROPERTY AND EQUIPMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PROPERTYANDEQUIPMENTTables</Role>
      <ShortName>PROPERTY AND EQUIPMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/PROPERTYANDEQUIPMENT</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETSTables</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETS</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - ACCRUED EXPENSES AND OTHER LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCRUEDEXPENSESANDOTHERLIABILITIESTables</Role>
      <ShortName>ACCRUED EXPENSES AND OTHER LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/ACCRUEDEXPENSESANDOTHERLIABILITIES</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - LEASING ARRANGEMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LEASINGARRANGEMENTSTables</Role>
      <ShortName>LEASING ARRANGEMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/LEASINGARRANGEMENTS</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - NOTES PAYABLE (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/NOTESPAYABLETables</Role>
      <ShortName>NOTES PAYABLE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/NOTESPAYABLE</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - TERM LOANS AND REVOLVING CREDIT FACILITY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/TERMLOANSANDREVOLVINGCREDITFACILITYTables</Role>
      <ShortName>TERM LOANS AND REVOLVING CREDIT FACILITY (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/TERMLOANSANDREVOLVINGCREDITFACILITY</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - SENIOR NOTES PAYABLE (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLETables</Role>
      <ShortName>SENIOR NOTES PAYABLE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SENIORNOTESPAYABLE</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - NONCONTROLLING INTERESTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/NONCONTROLLINGINTERESTSTables</Role>
      <ShortName>NONCONTROLLING INTERESTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/NONCONTROLLINGINTERESTS</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSTables</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERS</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - RESTRUCTURING CHARGE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RESTRUCTURINGCHARGETables</Role>
      <ShortName>RESTRUCTURING CHARGE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/RESTRUCTURINGCHARGE</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - INCOME TAXES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESTables</Role>
      <ShortName>INCOME TAXES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/INCOMETAXES</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - EARNINGS PER SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EARNINGSPERSHARETables</Role>
      <ShortName>EARNINGS PER SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/EARNINGSPERSHARE</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSTables</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANS</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - STOCKHOLDERS' EQUITY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITYTables</Role>
      <ShortName>STOCKHOLDERS' EQUITY (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/STOCKHOLDERSEQUITY</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - BUSINESS SEGMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTSTables</Role>
      <ShortName>BUSINESS SEGMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/BUSINESSSEGMENTS</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationTables</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformation</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - ORGANIZATION AND NATURE OF BUSINESS OPERATIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ORGANIZATIONANDNATUREOFBUSINESSOPERATIONSDetails</Role>
      <ShortName>ORGANIZATION AND NATURE OF BUSINESS OPERATIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/ORGANIZATIONANDNATUREOFBUSINESSOPERATIONS</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (a) Through (r) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeaThroughrDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (a) Through (r) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (s) Through (u) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativesThroughuDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (s) Through (u) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (v) Through (z) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativevThroughzDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (v) Through (z) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (aa) Through (ae) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeaaThroughaeDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (aa) Through (ae) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - VARIABLE INTEREST ENTITIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/VARIABLEINTERESTENTITIESNarrativeDetails</Role>
      <ShortName>VARIABLE INTEREST ENTITIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - VARIABLE INTEREST ENTITIES - Schedule of investments in the VIE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/VARIABLEINTERESTENTITIESScheduleofinvestmentsintheVIEDetails</Role>
      <ShortName>VARIABLE INTEREST ENTITIES - Schedule of investments in the VIE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - VARIABLE INTEREST ENTITIES - Schedule of assets and liabilities transferred to the BRC trust (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/VARIABLEINTERESTENTITIESScheduleofassetsandliabilitiestransferredtotheBRCtrustDetails</Role>
      <ShortName>VARIABLE INTEREST ENTITIES - Schedule of assets and liabilities transferred to the BRC trust (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - ACQUISITIONS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACQUISITIONSNarrativeDetails</Role>
      <ShortName>ACQUISITIONS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - ACQUISITIONS - Purchase price allocation schedule (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACQUISITIONSPurchasepriceallocationscheduleDetails</Role>
      <ShortName>ACQUISITIONS - Purchase price allocation schedule (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - ACQUISITIONS - Schedule of acquired indefinite-lived intangible assets by major class (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACQUISITIONSScheduleofacquiredindefinitelivedintangibleassetsbymajorclassDetails</Role>
      <ShortName>ACQUISITIONS - Schedule of acquired indefinite-lived intangible assets by major class (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE- Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALENarrativeDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE- Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALETables</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of assets and liabilities held for sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALEScheduleofassetsandliabilitiesheldforsaleDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of assets and liabilities held for sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>9955551 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of assets and liabilities from discontinued operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALEScheduleofassetsandliabilitiesfromdiscontinuedoperationsDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of assets and liabilities from discontinued operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>9955552 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of revenue from discontinued operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALEScheduleofrevenuefromdiscontinuedoperationsDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of revenue from discontinued operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>9955553 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of cash flows from discontinued operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALEScheduleofcashflowsfromdiscontinuedoperationsDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of cash flows from discontinued operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>9955554 - Disclosure - DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of supplemental disclosures from cash flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/DISCONTINUEDOPERATIONSANDASSETSHELDFORSALEScheduleofsupplementaldisclosuresfromcashflowsDetails</Role>
      <ShortName>DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE - Schedule of supplemental disclosures from cash flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>9955555 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of financial assets and liabilities measured on recurring basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSScheduleoffinancialassetsandliabilitiesmeasuredonrecurringbasisDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of financial assets and liabilities measured on recurring basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>9955556 - Disclosure - FAIR VALUE MEASUREMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>9955557 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of significant unobservable inputs of level 3 financial assets and liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSScheduleofsignificantunobservableinputsoflevel3financialassetsandliabilitiesDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of significant unobservable inputs of level 3 financial assets and liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>9955558 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of fair value measurement of level 3 financial assets and liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSScheduleoffairvaluemeasurementoflevel3financialassetsandliabilitiesDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of fair value measurement of level 3 financial assets and liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>9955559 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of equity securities valued under the measurement alternative on nonrecurring basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSScheduleofequitysecuritiesvaluedunderthemeasurementalternativeonnonrecurringbasisDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of equity securities valued under the measurement alternative on nonrecurring basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>9955560 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of financial assets measured on nonrecurring basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/FAIRVALUEMEASUREMENTSScheduleoffinancialassetsmeasuredonnonrecurringbasisDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of financial assets measured on nonrecurring basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>9955561 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Securities and other investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDSecuritiesandotherinvestmentsDetails</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Securities and other investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>9955562 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDNarrativeDetails</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDTables</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>9955563 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Carrying Values of Equity Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDCarryingValuesofEquitySecuritiesDetails</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Carrying Values of Equity Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>9955564 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Schedule of equity securities without readily determinable fair value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDScheduleofequitysecuritieswithoutreadilydeterminablefairvalueDetails</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Schedule of equity securities without readily determinable fair value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>9955565 - Disclosure - SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Schedule of equity method investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESANDOTHERINVESTMENTSOWNEDANDSECURITIESSOLDNOTYETPURCHASEDScheduleofequitymethodinvestmentsDetails</Role>
      <ShortName>SECURITIES AND OTHER INVESTMENTS OWNED AND SECURITIES SOLD NOT YET PURCHASED - Schedule of equity method investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>9955566 - Disclosure - SECURITIES LENDING - Schedule of contractual gross and net securities borrowing and lending balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESLENDINGScheduleofcontractualgrossandnetsecuritiesborrowingandlendingbalancesDetails</Role>
      <ShortName>SECURITIES LENDING - Schedule of contractual gross and net securities borrowing and lending balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>9955567 - Disclosure - SECURITIES LENDING - Schedule of contract value of securities leading transaction by type of collateral (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESLENDINGScheduleofcontractvalueofsecuritiesleadingtransactionbytypeofcollateralDetails</Role>
      <ShortName>SECURITIES LENDING - Schedule of contract value of securities leading transaction by type of collateral (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>9955568 - Disclosure - SECURITIES LENDING - Additional information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SECURITIESLENDINGAdditionalinformationDetails</Role>
      <ShortName>SECURITIES LENDING - Additional information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>9955569 - Disclosure - ACCOUNTS RECEIVABLE - Schedule of accounts receivable, net, from revenue from contracts with customers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCOUNTSRECEIVABLEScheduleofaccountsreceivablenetfromrevenuefromcontractswithcustomersDetails</Role>
      <ShortName>ACCOUNTS RECEIVABLE - Schedule of accounts receivable, net, from revenue from contracts with customers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>9955570 - Disclosure - ACCOUNTS RECEIVABLE- Schedule of allowance for doubtful accounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCOUNTSRECEIVABLEScheduleofallowancefordoubtfulaccountsDetails</Role>
      <ShortName>ACCOUNTS RECEIVABLE- Schedule of allowance for doubtful accounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>9955571 - Disclosure - LOANS RECEIVABLE, AT FAIR VALUE - Schedule of loans receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LOANSRECEIVABLEATFAIRVALUEScheduleofloansreceivableDetails</Role>
      <ShortName>LOANS RECEIVABLE, AT FAIR VALUE - Schedule of loans receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>107</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>9955572 - Disclosure - LOANS RECEIVABLE, AT FAIR VALUE - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LOANSRECEIVABLEATFAIRVALUEAdditionalInformationDetails</Role>
      <ShortName>LOANS RECEIVABLE, AT FAIR VALUE - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>108</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>9955573 - Disclosure - EQUITY METHOD INVESTMENTS - Schedule of investments accounted for under the equity method (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTSScheduleofinvestmentsaccountedforundertheequitymethodDetails</Role>
      <ShortName>EQUITY METHOD INVESTMENTS - Schedule of investments accounted for under the equity method (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>109</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>9955574 - Disclosure - EQUITY METHOD INVESTMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTSNarrativeDetails</Role>
      <ShortName>EQUITY METHOD INVESTMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>110</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>9955575 - Disclosure - EQUITY METHOD INVESTMENTS - Schedule of table contain summarized financial information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EQUITYMETHODINVESTMENTSScheduleoftablecontainsummarizedfinancialinformationDetails</Role>
      <ShortName>EQUITY METHOD INVESTMENTS - Schedule of table contain summarized financial information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>111</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>9955576 - Disclosure - PREPAID EXPENSES AND OTHER ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PREPAIDEXPENSESANDOTHERASSETSDetails</Role>
      <ShortName>PREPAID EXPENSES AND OTHER ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/PREPAIDEXPENSESANDOTHERASSETSTables</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>9955577 - Disclosure - PROPERTY AND EQUIPMENT - Schedule of property and equipment, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PROPERTYANDEQUIPMENTScheduleofpropertyandequipmentnetDetails</Role>
      <ShortName>PROPERTY AND EQUIPMENT - Schedule of property and equipment, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>113</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>9955578 - Disclosure - PROPERTY AND EQUIPMENT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/PROPERTYANDEQUIPMENTNarrativeDetails</Role>
      <ShortName>PROPERTY AND EQUIPMENT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>114</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>9955579 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETSNarrativeDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>115</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>9955580 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of carrying amount of goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofcarryingamountofgoodwillDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of carrying amount of goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>116</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>9955581 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of intangible assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofintangibleassetsDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of intangible assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>117</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>9955582 - Disclosure - ACCRUED EXPENSES AND OTHER LIABILITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/ACCRUEDEXPENSESANDOTHERLIABILITIESDetails</Role>
      <ShortName>ACCRUED EXPENSES AND OTHER LIABILITIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/ACCRUEDEXPENSESANDOTHERLIABILITIESTables</ParentRole>
      <Position>118</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>9955583 - Disclosure - LEASING ARRANGEMENTS - Lease cost (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LEASINGARRANGEMENTSLeasecostDetails</Role>
      <ShortName>LEASING ARRANGEMENTS - Lease cost (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>119</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>9955584 - Disclosure - LEASING ARRANGEMENTS - Schedule of maturities operating lease liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LEASINGARRANGEMENTSScheduleofmaturitiesoperatingleaseliabilitiesDetails</Role>
      <ShortName>LEASING ARRANGEMENTS - Schedule of maturities operating lease liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>120</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>9955585 - Disclosure - LEASING ARRANGEMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/LEASINGARRANGEMENTSNarrativeDetails</Role>
      <ShortName>LEASING ARRANGEMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>121</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>9955586 - Disclosure - NOTES PAYABLE - Schedule of notes payable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/NOTESPAYABLEScheduleofnotespayableDetails</Role>
      <ShortName>NOTES PAYABLE - Schedule of notes payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>122</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>9955587 - Disclosure - NOTES PAYABLE - Narrative (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/NOTESPAYABLENarrativeDetails</Role>
      <ShortName>NOTES PAYABLE - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>123</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>9955588 - Disclosure - TERM LOANS AND REVOLVING CREDIT FACILITY - Schedule of term loans and revolving credit facilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/TERMLOANSANDREVOLVINGCREDITFACILITYScheduleoftermloansandrevolvingcreditfacilitiesDetails</Role>
      <ShortName>TERM LOANS AND REVOLVING CREDIT FACILITY - Schedule of term loans and revolving credit facilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>124</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>9955589 - Disclosure - TERM LOANS AND REVOLVING CREDIT FACILITY - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/TERMLOANSANDREVOLVINGCREDITFACILITYNarrativeDetails</Role>
      <ShortName>TERM LOANS AND REVOLVING CREDIT FACILITY - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>125</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>9955590 - Disclosure - SENIOR NOTES PAYABLE - Schedule of senior notes payable, net (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLEScheduleofseniornotespayablenetDetails</Role>
      <ShortName>SENIOR NOTES PAYABLE - Schedule of senior notes payable, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>126</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>9955591 - Disclosure - SENIOR NOTES PAYABLE - Narrative (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLENarrativeDetails</Role>
      <ShortName>SENIOR NOTES PAYABLE - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>127</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>9955592 - Disclosure - SENIOR NOTES PAYABLE - Schedule of senior notes and new notes issued (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLEScheduleofseniornotesandnewnotesissuedDetails</Role>
      <ShortName>SENIOR NOTES PAYABLE - Schedule of senior notes and new notes issued (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>128</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>9955593 - Disclosure - SENIOR NOTES PAYABLE - Schedule of maturities (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.brcgh.com/role/SENIORNOTESPAYABLEScheduleofmaturitiesDetails</Role>
      <ShortName>SENIOR NOTES PAYABLE - Schedule of maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>129</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>9955594 - Disclosure - NONCONTROLLING INTERESTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/NONCONTROLLINGINTERESTSNarrativeDetails</Role>
      <ShortName>NONCONTROLLING INTERESTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>130</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>9955595 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>131</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>9955596 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of revenues from contracts with customers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSScheduleofrevenuesfromcontractswithcustomersDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of revenues from contracts with customers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>132</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>9955597 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of contract with customer, contract liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSScheduleofcontractwithcustomercontractliabilityDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of contract with customer, contract liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>133</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>9955598 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of revenue, remaining performance obligation, expected timing of satisfaction (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSScheduleofrevenueremainingperformanceobligationexpectedtimingofsatisfactionDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of revenue, remaining performance obligation, expected timing of satisfaction (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>134</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>9955599 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of contract with customer, contract asset, contract liability, and receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSScheduleofcontractwithcustomercontractassetcontractliabilityandreceivableDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of contract with customer, contract asset, contract liability, and receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>135</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>9955600 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of disaggregation of revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSScheduleofdisaggregationofrevenueDetails</Role>
      <ShortName>REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of disaggregation of revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>136</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>9955601 - Disclosure - RESTRUCTURING CHARGE - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RESTRUCTURINGCHARGENarrativeDetails</Role>
      <ShortName>RESTRUCTURING CHARGE - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>137</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>9955602 - Disclosure - RESTRUCTURING CHARGE - Schedule of changes in accrued restructuring charge (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RESTRUCTURINGCHARGEScheduleofchangesinaccruedrestructuringchargeDetails</Role>
      <ShortName>RESTRUCTURING CHARGE - Schedule of changes in accrued restructuring charge (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>138</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>9955603 - Disclosure - RESTRUCTURING CHARGE - Schedule of summarize the restructuring activities by reportable segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RESTRUCTURINGCHARGEScheduleofsummarizetherestructuringactivitiesbyreportablesegmentDetails</Role>
      <ShortName>RESTRUCTURING CHARGE - Schedule of summarize the restructuring activities by reportable segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>139</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>9955604 - Disclosure - INCOME TAXES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESNarrativeDetails</Role>
      <ShortName>INCOME TAXES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>140</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>9955605 - Disclosure - INCOME TAXES - Schedule of provision (benefit) for income taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESScheduleofprovisionbenefitforincometaxesDetails</Role>
      <ShortName>INCOME TAXES - Schedule of provision (benefit) for income taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>141</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>9955606 - Disclosure - INCOME TAXES - Schedule of Income taxes paid (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESScheduleofIncometaxespaidDetails</Role>
      <ShortName>INCOME TAXES - Schedule of Income taxes paid (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>142</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>9955607 - Disclosure - INCOME TAXES - Schedule of reconciliation effective tax rate for income (loss) before income taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESScheduleofreconciliationeffectivetaxrateforincomelossbeforeincometaxesDetails</Role>
      <ShortName>INCOME TAXES - Schedule of reconciliation effective tax rate for income (loss) before income taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>143</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>9955608 - Disclosure - INCOME TAXES - Schedule of deferred income tax assets (liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESScheduleofdeferredincometaxassetsliabilitiesDetails</Role>
      <ShortName>INCOME TAXES - Schedule of deferred income tax assets (liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>144</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>9955609 - Disclosure - INCOME TAXES - Schedule of reconciliation of the amounts of gross unrecognized tax benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/INCOMETAXESScheduleofreconciliationoftheamountsofgrossunrecognizedtaxbenefitsDetails</Role>
      <ShortName>INCOME TAXES - Schedule of reconciliation of the amounts of gross unrecognized tax benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>145</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>9955610 - Disclosure - EARNINGS PER SHARE - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EARNINGSPERSHARENarrativeDetails</Role>
      <ShortName>EARNINGS PER SHARE - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>146</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>9955611 - Disclosure - EARNINGS PER SHARE - Schedule of basic and diluted earnings per share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/EARNINGSPERSHAREScheduleofbasicanddilutedearningspershareDetails</Role>
      <ShortName>EARNINGS PER SHARE - Schedule of basic and diluted earnings per share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>147</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R148.htm</HtmlFileName>
      <LongName>9955612 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of employee benefit plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSScheduleofemployeebenefitplanDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of employee benefit plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>148</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R149.htm</HtmlFileName>
      <LongName>9955613 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of employee stock incentive plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSScheduleofemployeestockincentiveplansDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of employee stock incentive plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>149</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R150.htm</HtmlFileName>
      <LongName>9955614 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSNarrativeDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>150</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R151.htm</HtmlFileName>
      <LongName>9955615 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of equity incentive award activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSScheduleofequityincentiveawardactivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of equity incentive award activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>151</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R152.htm</HtmlFileName>
      <LongName>9955616 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of restricted stock award activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSScheduleofrestrictedstockawardactivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of restricted stock award activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>152</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R153.htm</HtmlFileName>
      <LongName>9955617 - Disclosure - SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SHAREBASEDPAYMENTSANDBENEFITPLANSScheduleofStockOptionActivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS AND BENEFIT PLANS - Schedule of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>153</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R154.htm</HtmlFileName>
      <LongName>9955618 - Disclosure - STOCKHOLDERS' EQUITY - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITYNarrativeDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>154</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R155.htm</HtmlFileName>
      <LongName>9955619 - Disclosure - STOCKHOLDERS' EQUITY - Schedule of stockholders' equity note, warrants or rights (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITYScheduleofstockholdersequitynotewarrantsorrightsDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Schedule of stockholders' equity note, warrants or rights (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>155</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R156.htm</HtmlFileName>
      <LongName>9955620 - Disclosure - STOCKHOLDERS' EQUITY - Schedule of dividends payable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITYScheduleofdividendspayableDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Schedule of dividends payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>156</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R157.htm</HtmlFileName>
      <LongName>9955621 - Disclosure - STOCKHOLDERS' EQUITY - Schedule of preferred stock dividends payable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/STOCKHOLDERSEQUITYScheduleofpreferredstockdividendspayableDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Schedule of preferred stock dividends payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>157</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R158.htm</HtmlFileName>
      <LongName>9955622 - Disclosure - NET CAPITAL REQUIREMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/NETCAPITALREQUIREMENTSDetails</Role>
      <ShortName>NET CAPITAL REQUIREMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/NETCAPITALREQUIREMENTS</ParentRole>
      <Position>158</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R159.htm</HtmlFileName>
      <LongName>9955623 - Disclosure - RELATED PARTY TRANSACTIONS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/RELATEDPARTYTRANSACTIONSNarrativeDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>159</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R160.htm</HtmlFileName>
      <LongName>9955624 - Disclosure - BUSINESS SEGMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTSNarrativeDetails</Role>
      <ShortName>BUSINESS SEGMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>160</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R161.htm</HtmlFileName>
      <LongName>9955625 - Disclosure - BUSINESS SEGMENTS - Schedule of reportable segments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTSScheduleofreportablesegmentsDetails</Role>
      <ShortName>BUSINESS SEGMENTS - Schedule of reportable segments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>161</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R162.htm</HtmlFileName>
      <LongName>9955626 - Disclosure - BUSINESS SEGMENTS - Schedule of revenues by geographical area (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTSScheduleofrevenuesbygeographicalareaDetails</Role>
      <ShortName>BUSINESS SEGMENTS - Schedule of revenues by geographical area (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>162</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R163.htm</HtmlFileName>
      <LongName>9955627 - Disclosure - BUSINESS SEGMENTS - Schedule of long lived assets by geographical area (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/BUSINESSSEGMENTSScheduleoflonglivedassetsbygeographicalareaDetails</Role>
      <ShortName>BUSINESS SEGMENTS - Schedule of long lived assets by geographical area (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>163</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R164.htm</HtmlFileName>
      <LongName>9955628 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/COMMITMENTSANDCONTINGENCIESDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/COMMITMENTSANDCONTINGENCIES</ParentRole>
      <Position>164</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R165.htm</HtmlFileName>
      <LongName>9955629 - Disclosure - SUBSEQUENT EVENT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/SUBSEQUENTEVENTDetails</Role>
      <ShortName>SUBSEQUENT EVENT (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/SUBSEQUENTEVENT</ParentRole>
      <Position>165</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R166.htm</HtmlFileName>
      <LongName>9955630 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed balance sheets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationCondensedbalancesheetsDetails</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed balance sheets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>166</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R167.htm</HtmlFileName>
      <LongName>9955631 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed statements of operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationCondensedstatementsofoperationsDetails</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed statements of operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>167</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R168.htm</HtmlFileName>
      <LongName>9955632 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed statements of cash flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationCondensedstatementsofcashflowsDetails</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Condensed statements of cash flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>168</Position>
    </Report>
    <Report instance="rily-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R169.htm</HtmlFileName>
      <LongName>9955633 - Disclosure - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationNarrativeDetails</Role>
      <ShortName>CONDENSED FINANCIAL INFORMATION OF REGISTRANT Parent Company Only Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.brcgh.com/role/CONDENSEDFINANCIALINFORMATIONOFREGISTRANTParentCompanyOnlyInformationTables</ParentRole>
      <Position>169</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/A" isDefinitelyFs="true" isUsgaap="true" original="rily-20251231.htm">rily-20251231.htm</File>
    <File>rily-20251231.xsd</File>
    <File>rily-20251231_cal.xml</File>
    <File>rily-20251231_def.xml</File>
    <File>rily-20251231_lab.xml</File>
    <File>rily-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>rily-20251231_g1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="24">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="3114">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="57">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="5">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
