<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.19.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>81</ContextCount>
  <ElementCount>177</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>30</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>001 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>002 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/BalanceSheet</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>003 - Statement - CONSOLIDATED BALANCE SHEETS [Parenthetical]</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/BalanceSheetParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS [Parenthetical]</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>004 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>005 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/CashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>006 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' (DEFICIT) EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSDEFICITEQUITY</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF SHAREHOLDERS' (DEFICIT) EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>007 - Disclosure - NATURE OF OPERATIONS AND GOING CONCERN</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsNatureOfOperationsTextBlock</Role>
      <ShortName>NATURE OF OPERATIONS AND GOING CONCERN</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>008 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlock</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>009 - Disclosure - MINERAL PROPERTIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsMineralIndustriesDisclosuresTextBlock</Role>
      <ShortName>MINERAL PROPERTIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>010 - Disclosure - CAPITAL ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsPropertyPlantAndEquipmentDisclosureTextBlock</Role>
      <ShortName>CAPITAL ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>011 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsRelatedPartyTransactionsDisclosureTextBlock</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>012 - Disclosure - DISCONTINUED OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock</Role>
      <ShortName>DISCONTINUED OPERATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>013 - Disclosure - SHARE CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock</Role>
      <ShortName>SHARE CAPITAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>014 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>015 - Disclosure - FINANCIAL RISK MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsFinancialRiskManagementDisclosureTextBlock</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>016 - Disclosure - ENVIRONMENTAL CONTINGENCY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsEnvironmentalLossContingencyDisclosureTextBlock</Role>
      <ShortName>ENVIRONMENTAL CONTINGENCY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>017 - Disclosure - SUBSEQUENT EVENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/SUBSEQUENTEVENT</Role>
      <ShortName>SUBSEQUENT EVENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>018 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>019 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlockTables</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlock</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>020 - Disclosure - CAPITAL ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsPropertyPlantAndEquipmentDisclosureTextBlockTables</Role>
      <ShortName>CAPITAL ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsPropertyPlantAndEquipmentDisclosureTextBlock</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>021 - Disclosure - DISCONTINUED OPERATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlockTables</Role>
      <ShortName>DISCONTINUED OPERATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>022 - Disclosure - SHARE CAPITAL (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables</Role>
      <ShortName>SHARE CAPITAL (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>023 - Disclosure - INCOME TAXES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlockTables</Role>
      <ShortName>INCOME TAXES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>024 - Disclosure - FINANCIAL RISK MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/NotesToFinancialStatementsFinancialRiskManagementDisclosureTextBlockTables</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsFinancialRiskManagementDisclosureTextBlock</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>025 - Disclosure - NATURE OF OPERATIONS AND GOING CONCERN (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureNatureOfOperationsDetails</Role>
      <ShortName>NATURE OF OPERATIONS AND GOING CONCERN (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsNatureOfOperationsTextBlock</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>027 - Disclosure - MINERAL PROPERTIES (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureMineralIndustriesDisclosuresTextBlockDetails</Role>
      <ShortName>MINERAL PROPERTIES (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsMineralIndustriesDisclosuresTextBlock</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>028 - Disclosure - RELATED PARTY TRANSACTIONS (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureRelatedPartyTransactionsDisclosureTextBlockDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsRelatedPartyTransactionsDisclosureTextBlock</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>029 - Disclosure - SHARE CAPITAL (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureStockholdersEquityNoteDisclosureTextBlockDetails</Role>
      <ShortName>SHARE CAPITAL (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>030 - Disclosure - INCOME TAXES (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureIncomeTaxDisclosureTextBlockDetails</Role>
      <ShortName>INCOME TAXES (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlockTables</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>031 - Disclosure - FINANCIAL RISK MANAGEMENT (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureFinancialRiskManagementDisclosureTextBlockDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/NotesToFinancialStatementsFinancialRiskManagementDisclosureTextBlockTables</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>032 - Disclosure - SUBSEQUENT EVENTS (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureSubsequentEventsTextBlockDetails</Role>
      <ShortName>SUBSEQUENT EVENTS (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gentorresources.com/role/SUBSEQUENTEVENT</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>033 - Disclosure - Schedule Of Capital Assets Depreciation Method (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/Disclosurescheduleofcapitalassetsdepreciationmethodtabletextblockdetails</Role>
      <ShortName>Schedule Of Capital Assets Depreciation Method (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>034 - Disclosure - Schedule of Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/ScheduleOfPropertyPlantAndEquipmentDetails</Role>
      <ShortName>Schedule of Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>035 - Disclosure - Schedule of Results of the Discontinued Operation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfResultsOfTheDiscontinuedOperationTableTextBlockDetails</Role>
      <ShortName>Schedule of Results of the Discontinued Operation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>036 - Disclosure - Schedule of Cash Flows from the Discontinued Operation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfCashFlowsFromTheDiscontinuedOperationTableTextBlockDetails</Role>
      <ShortName>Schedule of Cash Flows from the Discontinued Operation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>037 - Disclosure - Schedule of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfShareBasedCompensationStockOptionsActivityAndWarrantsOrRightsActivityTableTextBlockDetails</Role>
      <ShortName>Schedule of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>038 - Disclosure - Schedule of Derivative Financial Instruments Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfDerivativeFinancialInstrumentsActivityTableTextBlockDetails</Role>
      <ShortName>Schedule of Derivative Financial Instruments Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>039 - Disclosure - Schedule of Components of Income Tax Expense (Benefit) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlockDetails</Role>
      <ShortName>Schedule of Components of Income Tax Expense (Benefit) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>040 - Disclosure - Schedule of Deferred Tax Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlockDetails</Role>
      <ShortName>Schedule of Deferred Tax Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>041 - Disclosure - Summary of Operating Loss Carryforwards (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureSummaryOfOperatingLossCarryforwardsTextBlockDetails</Role>
      <ShortName>Summary of Operating Loss Carryforwards (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="gntof-20181231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>042 - Disclosure - Schedule Of Foreign Currency Risk On Net Working Capital and Sensitivity Analysis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gentorresources.com/role/DisclosureScheduleOfForeignCurrencyRiskOnNetWorkingCapitalAndSensitivityAnalysisTableTextBlockDetails</Role>
      <ShortName>Schedule Of Foreign Currency Risk On Net Working Capital and Sensitivity Analysis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>gntof-20181231.xml</File>
    <File>gntof-20181231.xsd</File>
    <File>gntof-20181231_cal.xml</File>
    <File>gntof-20181231_def.xml</File>
    <File>gntof-20181231_lab.xml</File>
    <File>gntof-20181231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2018-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
