<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>155</ContextCount>
  <ElementCount>228</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>59</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/UNAUDITEDINTERIMCONDENSEDCONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY</Role>
      <ShortName>UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - GENERAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/GENERAL</Role>
      <ShortName>GENERAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/ACCOUNTINGPOLICIES</Role>
      <ShortName>ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - RECENT ACCOUNTING PRONOUNCEMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/RECENTACCOUNTINGPRONOUNCEMENTS</Role>
      <ShortName>RECENT ACCOUNTING PRONOUNCEMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - EARNINGS PER SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/EARNINGSPERSHARE</Role>
      <ShortName>EARNINGS PER SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - CASH, CASH EQUIVALENTS AND RESTRICTED CASH</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/CASHCASHEQUIVALENTSANDRESTRICTEDCASH</Role>
      <ShortName>CASH, CASH EQUIVALENTS AND RESTRICTED CASH</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - OTHER CURRENT ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTASSETS</Role>
      <ShortName>OTHER CURRENT ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - OTHER CURRENT LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTLIABILITIES</Role>
      <ShortName>OTHER CURRENT LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - VESSELS AND EQUIPMENT, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/VESSELSANDEQUIPMENTNET</Role>
      <ShortName>VESSELS AND EQUIPMENT, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - SHORT TERM AND LONG-TERM DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBT</Role>
      <ShortName>SHORT TERM AND LONG-TERM DEBT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTS</Role>
      <ShortName>FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FAIRVALUEOFFINANCIALASSETSANDLIABILITIES</Role>
      <ShortName>FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/RELATEDPARTYTRANSACTIONS</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - SHARE CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHARECAPITAL</Role>
      <ShortName>SHARE CAPITAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - TREASURY SHARES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/TREASURYSHARES</Role>
      <ShortName>TREASURY SHARES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - SHARE BASED COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHAREBASEDCOMPENSATION</Role>
      <ShortName>SHARE BASED COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - OPERATING LEASES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OPERATINGLEASES</Role>
      <ShortName>OPERATING LEASES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - SUBSEQUENT EVENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SUBSEQUENTEVENTS</Role>
      <ShortName>SUBSEQUENT EVENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/ACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - EARNINGS PER SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/EARNINGSPERSHARETables</Role>
      <ShortName>EARNINGS PER SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/EARNINGSPERSHARE</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - CASH, CASH EQUIVALENTS AND RESTRICTED CASH (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/CASHCASHEQUIVALENTSANDRESTRICTEDCASHTables</Role>
      <ShortName>CASH, CASH EQUIVALENTS AND RESTRICTED CASH (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/CASHCASHEQUIVALENTSANDRESTRICTEDCASH</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - OTHER CURRENT ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTASSETSTables</Role>
      <ShortName>OTHER CURRENT ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/OTHERCURRENTASSETS</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - OTHER CURRENT LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTLIABILITIESTables</Role>
      <ShortName>OTHER CURRENT LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/OTHERCURRENTLIABILITIES</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - VESSELS AND EQUIPMENT, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/VESSELSANDEQUIPMENTNETTables</Role>
      <ShortName>VESSELS AND EQUIPMENT, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/VESSELSANDEQUIPMENTNET</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - SHORT TERM AND LONG-TERM DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBTTables</Role>
      <ShortName>SHORT TERM AND LONG-TERM DEBT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBT</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTSTables</Role>
      <ShortName>FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/FINANCIALINSTRUMENTS</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FAIRVALUEOFFINANCIALASSETSANDLIABILITIESTables</Role>
      <ShortName>FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/FAIRVALUEOFFINANCIALASSETSANDLIABILITIES</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - RELATED PARTY TRANSACTIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/RELATEDPARTYTRANSACTIONSTables</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/RELATEDPARTYTRANSACTIONS</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - OPERATING LEASES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OPERATINGLEASESTables</Role>
      <ShortName>OPERATING LEASES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/OPERATINGLEASES</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - GENERAL (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/GENERALDetails</Role>
      <ShortName>GENERAL (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/GENERAL</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - EARNINGS PER SHARE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/EARNINGSPERSHAREDetails</Role>
      <ShortName>EARNINGS PER SHARE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/EARNINGSPERSHARETables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - CASH, CASH EQUIVALENTS AND RESTRICTED CASH (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/CASHCASHEQUIVALENTSANDRESTRICTEDCASHDetails</Role>
      <ShortName>CASH, CASH EQUIVALENTS AND RESTRICTED CASH (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/CASHCASHEQUIVALENTSANDRESTRICTEDCASHTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - OTHER CURRENT ASSETS - Schedule of Other Current Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTASSETSScheduleofOtherCurrentAssetsDetails</Role>
      <ShortName>OTHER CURRENT ASSETS - Schedule of Other Current Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - OTHER CURRENT ASSETS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTASSETSNarrativeDetails</Role>
      <ShortName>OTHER CURRENT ASSETS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - OTHER CURRENT LIABILITIES - Schedule of Other Current Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OTHERCURRENTLIABILITIESScheduleofOtherCurrentLiabilitiesDetails</Role>
      <ShortName>OTHER CURRENT LIABILITIES - Schedule of Other Current Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - VESSELS AND EQUIPMENT, NET - Summary of Vessels and Equipment, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/VESSELSANDEQUIPMENTNETSummaryofVesselsandEquipmentNetDetails</Role>
      <ShortName>VESSELS AND EQUIPMENT, NET - Summary of Vessels and Equipment, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - SHORT TERM AND LONG-TERM DEBT - Short Term and Long-Term Debt Components (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBTShortTermandLongTermDebtComponentsDetails</Role>
      <ShortName>SHORT TERM AND LONG-TERM DEBT - Short Term and Long-Term Debt Components (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - SHORT TERM AND LONG-TERM DEBT - Capital Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBTCapitalCommitmentsDetails</Role>
      <ShortName>SHORT TERM AND LONG-TERM DEBT - Capital Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - SHORT TERM AND LONG-TERM DEBT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHORTTERMANDLONGTERMDEBTNarrativeDetails</Role>
      <ShortName>SHORT TERM AND LONG-TERM DEBT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - FINANCIAL INSTRUMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTSNarrativeDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - FINANCIAL INSTRUMENTS - Schedule of Derivative Notional Amounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTSScheduleofDerivativeNotionalAmountsDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Schedule of Derivative Notional Amounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - FINANCIAL INSTRUMENTS - Schedule of Gain (Loss) on Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTSScheduleofGainLossonDerivativesDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Schedule of Gain (Loss) on Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - FINANCIAL INSTRUMENTS - Movements in Derivative Instruments, Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FINANCIALINSTRUMENTSMovementsinDerivativeInstrumentsAssetsandLiabilitiesDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Movements in Derivative Instruments, Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/FAIRVALUEOFFINANCIALASSETSANDLIABILITIESDetails</Role>
      <ShortName>FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/FAIRVALUEOFFINANCIALASSETSANDLIABILITIESTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - RELATED PARTY TRANSACTIONS - Schedule of Related Party Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/RELATEDPARTYTRANSACTIONSScheduleofRelatedPartyBalancesDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Schedule of Related Party Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - RELATED PARTY TRANSACTIONS - Schedule of Related Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/RELATEDPARTYTRANSACTIONSScheduleofRelatedPartyTransactionsDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Schedule of Related Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - SHARE CAPITAL (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHARECAPITALDetails</Role>
      <ShortName>SHARE CAPITAL (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/SHARECAPITAL</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - TREASURY SHARES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/TREASURYSHARESDetails</Role>
      <ShortName>TREASURY SHARES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/TREASURYSHARES</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - SHARE BASED COMPENSATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SHAREBASEDCOMPENSATIONDetails</Role>
      <ShortName>SHARE BASED COMPENSATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/SHAREBASEDCOMPENSATION</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - OPERATING LEASES - Committed Time Charter Revenues (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/OPERATINGLEASESCommittedTimeCharterRevenuesDetails</Role>
      <ShortName>OPERATING LEASES - Committed Time Charter Revenues (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="flng-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - SUBSEQUENT EVENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.flexlng.com/role/SUBSEQUENTEVENTSDetails</Role>
      <ShortName>SUBSEQUENT EVENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.flexlng.com/role/SUBSEQUENTEVENTS</ParentRole>
      <Position>57</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="6-K" isDefinitelyFs="true" isUsgaap="true" original="flng-20260630.htm">flng-20260630.htm</File>
    <File>flng-20260630.xsd</File>
    <File>flng-20260630_cal.xml</File>
    <File>flng-20260630_def.xml</File>
    <File>flng-20260630_lab.xml</File>
    <File>flng-20260630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="499">http://fasb.org/us-gaap/2026</BaseTaxonomy>
    <BaseTaxonomy items="13">http://xbrl.sec.gov/dei/2026</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
