<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>311</ContextCount>
  <ElementCount>381</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>83</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030 - Statement - CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDANDCOMBINEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040 - Statement - CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDANDCOMBINEDSTATEMENTSOFCOMPREHENSIVELOSSINCOME</Role>
      <ShortName>CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050 - Statement - CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF EQUITY (DEFICIT)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDANDCOMBINEDSTATEMENTSOFEQUITYDEFICIT</Role>
      <ShortName>CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF EQUITY (DEFICIT)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100060 - Statement - CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/StatementCONDENSEDCONSOLIDATEDANDCOMBINEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONDENSED CONSOLIDATED AND COMBINED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100070 - Disclosure - ORGANIZATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureORGANIZATION</Role>
      <ShortName>ORGANIZATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>100080 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>100090 - Disclosure - BUSINESS COMBINATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureBUSINESSCOMBINATION</Role>
      <ShortName>BUSINESS COMBINATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>100100 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETS</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>100110 - Disclosure - LONG-TERM DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBT</Role>
      <ShortName>LONG-TERM DEBT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>100120 - Disclosure - EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureEQUITY</Role>
      <ShortName>EQUITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>100130 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATION</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>100140 - Disclosure - NONCONTROLLING INTEREST</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureNONCONTROLLINGINTEREST</Role>
      <ShortName>NONCONTROLLING INTEREST</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>100150 - Disclosure - REVENUE RECOGNITION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureREVENUERECOGNITION</Role>
      <ShortName>REVENUE RECOGNITION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>100160 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureRELATEDPARTYTRANSACTIONS</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>100170 - Disclosure - SEGMENT AND GEOGRAPHICAL INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSEGMENTANDGEOGRAPHICALINFORMATION</Role>
      <ShortName>SEGMENT AND GEOGRAPHICAL INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>100180 - Disclosure - CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS</Role>
      <ShortName>CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>100190 - Disclosure - FAIR VALUE MEASUREMENTS AND DERIVATIVES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVES</Role>
      <ShortName>FAIR VALUE MEASUREMENTS AND DERIVATIVES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>100200 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureINCOMETAXES</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>100210 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureCOMMITMENTSANDCONTINGENCIES</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>100220 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>100230 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>100240 - Disclosure - BUSINESS COMBINATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureBUSINESSCOMBINATIONTables</Role>
      <ShortName>BUSINESS COMBINATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureBUSINESSCOMBINATION</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>100250 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETSTables</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETS</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>100260 - Disclosure - LONG-TERM DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBTTables</Role>
      <ShortName>LONG-TERM DEBT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBT</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>100270 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONTables</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATION</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>100280 - Disclosure - NONCONTROLLING INTEREST (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureNONCONTROLLINGINTERESTTables</Role>
      <ShortName>NONCONTROLLING INTEREST (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureNONCONTROLLINGINTEREST</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>100290 - Disclosure - REVENUE RECOGNITION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureREVENUERECOGNITIONTables</Role>
      <ShortName>REVENUE RECOGNITION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureREVENUERECOGNITION</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>100300 - Disclosure - SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSEGMENTANDGEOGRAPHICALINFORMATIONTables</Role>
      <ShortName>SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureSEGMENTANDGEOGRAPHICALINFORMATION</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>100310 - Disclosure - CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSTables</Role>
      <ShortName>CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>100320 - Disclosure - FAIR VALUE MEASUREMENTS AND DERIVATIVES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVESTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS AND DERIVATIVES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVES</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>100330 - Disclosure - ORGANIZATION - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureORGANIZATIONAdditionalInformationDetails</Role>
      <ShortName>ORGANIZATION - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>100340 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESAdditionalInformationDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>100350 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of (Loss) Income per Basic and Diluted Share Calculation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESSummaryOfLossIncomePerBasicAndDilutedShareCalculationDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of (Loss) Income per Basic and Diluted Share Calculation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>100360 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Basic and Diluted per Share Computation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESSummaryOfBasicAndDilutedPerShareComputationDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Basic and Diluted per Share Computation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>100370 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Weighted-Average Number of Antidilutive Potential Common Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESSummaryOfWeightedAverageNumberOfAntidilutivePotentialCommonSharesDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Weighted-Average Number of Antidilutive Potential Common Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>100380 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Reconciles Cash, Cash Equivalents and Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESSummaryOfReconcilesCashCashEquivalentsAndRestrictedCashDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Reconciles Cash, Cash Equivalents and Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>100390 - Disclosure - BUSINESS COMBINATION - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureBUSINESSCOMBINATIONAdditionalInformationDetails</Role>
      <ShortName>BUSINESS COMBINATION - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>100400 - Disclosure - BUSINESS COMBINATION - Schedule of Unaudited Supplemental Pro Forma (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureBUSINESSCOMBINATIONScheduleOfUnauditedSupplementalProFormaDetails</Role>
      <ShortName>BUSINESS COMBINATION - Schedule of Unaudited Supplemental Pro Forma (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>100410 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETSAdditionalInformationDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>100420 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of Changes in Carrying Amount of Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETSSummaryOfChangesInCarryingAmountOfGoodwillDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of Changes in Carrying Amount of Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>100430 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of Cost, Accumulated Amortization, and Net Balance of the Definite-Lived Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureGOODWILLANDOTHERINTANGIBLEASSETSSummaryOfCostAccumulatedAmortizationAndNetBalanceOfDefiniteLivedIntangibleAssetsDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of Cost, Accumulated Amortization, and Net Balance of the Definite-Lived Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>100440 - Disclosure - LONG-TERM DEBT - Summary of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBTSummaryOfLongTermDebtDetails</Role>
      <ShortName>LONG-TERM DEBT - Summary of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>100450 - Disclosure - LONG-TERM DEBT - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBTAdditionalInformationDetails</Role>
      <ShortName>LONG-TERM DEBT - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>100460 - Disclosure - LONG-TERM DEBT - Schedule of Principal Repayments on Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureLONGTERMDEBTScheduleOfPrincipalRepaymentsOnLongTermDebtDetails</Role>
      <ShortName>LONG-TERM DEBT - Schedule of Principal Repayments on Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>100470 - Disclosure - EQUITY - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureEQUITYAdditionalInformationDetails</Role>
      <ShortName>EQUITY - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>100480 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONAdditionalInformationDetails</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>100490 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION - Summary of Restricted Share Unit Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONSummaryOfRestrictedShareUnitActivityDetails</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION - Summary of Restricted Share Unit Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>100500 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION - Summary of Hurdle Price Activity of PSU's (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONSummaryOfHurdlePriceActivityOfPSUSDetails</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION - Summary of Hurdle Price Activity of PSU's (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>100510 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION - Schedule of Grant Date Fair Value of PSU's (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONScheduleOfGrantDateFairValueOfPSUSDetails</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION - Schedule of Grant Date Fair Value of PSU's (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>100520 - Disclosure - STOCK-BASED EMPLOYEE COMPENSATION - Summary of Performance Share Unit Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSTOCKBASEDEMPLOYEECOMPENSATIONSummaryOfPerformanceShareUnitActivityDetails</Role>
      <ShortName>STOCK-BASED EMPLOYEE COMPENSATION - Summary of Performance Share Unit Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>100530 - Disclosure - NONCONTROLLING INTEREST - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureNONCONTROLLINGINTERESTAdditionalInformationDetails</Role>
      <ShortName>NONCONTROLLING INTEREST - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>100540 - Disclosure - NONCONTROLLING INTEREST - Summary of Total Equity Adjusted Due to Purchase of Noncontrolling Interest (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureNONCONTROLLINGINTERESTSummaryOfTotalEquityAdjustedDueToPurchaseOfNoncontrollingInterestDetail</Role>
      <ShortName>NONCONTROLLING INTEREST - Summary of Total Equity Adjusted Due to Purchase of Noncontrolling Interest (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>100550 - Disclosure - REVENUE RECOGNITION - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureREVENUERECOGNITIONAdditionalInformationDetails</Role>
      <ShortName>REVENUE RECOGNITION - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>100560 - Disclosure - REVENUE RECOGNITION - Summary of Disaggregation of Revenue By Revenue Source and Operating Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureREVENUERECOGNITIONSummaryOfDisaggregationOfRevenueByRevenueSourceAndOperatingSegmentDetails</Role>
      <ShortName>REVENUE RECOGNITION - Summary of Disaggregation of Revenue By Revenue Source and Operating Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>100570 - Disclosure - RELATED PARTY TRANSACTIONS - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureRELATEDPARTYTRANSACTIONSAdditionalInformationDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>100580 - Disclosure - SEGMENT AND GEOGRAPHICAL INFORMATION - Summary of Geographic information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureSEGMENTANDGEOGRAPHICALINFORMATIONSummaryOfGeographicInformationDetails</Role>
      <ShortName>SEGMENT AND GEOGRAPHICAL INFORMATION - Summary of Geographic information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>100590 - Disclosure - CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSSummaryOfChangesInAccumulatedOtherComprehensiveIncomeLossDetails</Role>
      <ShortName>CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://onespaworld.com/20200930/taxonomy/role/DisclosureCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>100600 - Disclosure - FAIR VALUE MEASUREMENTS AND DERIVATIVES - Summary of Fair Value on Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVESSummaryOfFairValueOnRecurringBasisDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS AND DERIVATIVES - Summary of Fair Value on Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>100610 - Disclosure - FAIR VALUE MEASUREMENTS AND DERIVATIVES - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVESAdditionalInformationDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS AND DERIVATIVES - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>100620 - Disclosure - FAIR VALUE MEASUREMENTS AND DERIVATIVES - Summary of Interest Rate Swap Contract (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureFAIRVALUEMEASUREMENTSANDDERIVATIVESSummaryOfInterestRateSwapContractDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS AND DERIVATIVES - Summary of Interest Rate Swap Contract (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>100630 - Disclosure - INCOME TAXES - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureINCOMETAXESAdditionalInformationDetails</Role>
      <ShortName>INCOME TAXES - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="osw-20200930.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>100640 - Disclosure - COMMITMENTS AND CONTINGENCIES - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://onespaworld.com/20200930/taxonomy/role/DisclosureCOMMITMENTSANDCONTINGENCIESAdditionalInformationDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>osw-20200930.xml</File>
    <File>osw-20200930.xsd</File>
    <File>osw-20200930_cal.xml</File>
    <File>osw-20200930_def.xml</File>
    <File>osw-20200930_lab.xml</File>
    <File>osw-20200930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
