<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.8.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>409</ContextCount>
  <ElementCount>405</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>90</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - DOCUMENT AND ENTITY INFORMATION Document</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DocumentAndEntityInformationDocument</Role>
      <ShortName>DOCUMENT AND ENTITY INFORMATION Document</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME/(LOSS)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncomeLoss</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME/(LOSS)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001001 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME/(LOSS) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME/(LOSS) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1002001 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1003000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1003001 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedStatementsOfCashFlowsParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1004000 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ConsolidatedStatementsOfChangesInShareholdersEquity</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - NATURE OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/NatureOfOperations</Role>
      <ShortName>NATURE OF OPERATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - BASIS OF PRESENTATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/BasisOfPresentation</Role>
      <ShortName>BASIS OF PRESENTATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - SUMMARY OF ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPolicies</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - CRITICAL ACCOUNTING JUDGEMENTS, ESTIMATES AND ASSUMPTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CriticalAccountingJudgementsEstimatesAndAssumptions</Role>
      <ShortName>CRITICAL ACCOUNTING JUDGEMENTS, ESTIMATES AND ASSUMPTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstruments</Role>
      <ShortName>FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - INVENTORIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/Inventories</Role>
      <ShortName>INVENTORIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - MINING INTERESTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/MiningInterests</Role>
      <ShortName>MINING INTERESTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2125100 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxes</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2128100 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/AccountsPayableAndAccruedLiabilities</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2131100 - Disclosure - REHABILITATION PROVISIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RehabilitationProvisions</Role>
      <ShortName>REHABILITATION PROVISIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2134100 - Disclosure - DEFERRED REVENUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DeferredRevenue</Role>
      <ShortName>DEFERRED REVENUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2137100 - Disclosure - DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/Debt</Role>
      <ShortName>DEBT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2140100 - Disclosure - SHARE CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareCapital</Role>
      <ShortName>SHARE CAPITAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2143100 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CommitmentsAndContingencies</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2146100 - Disclosure - SHARE-BASED COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensation</Role>
      <ShortName>SHARE-BASED COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2149100 - Disclosure - INCOME/(LOSS) PER COMMON SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeLossPerCommonShare</Role>
      <ShortName>INCOME/(LOSS) PER COMMON SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2152100 - Disclosure - REVENUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/Revenue</Role>
      <ShortName>REVENUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2155100 - Disclosure - COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CostOfSalesExcludingDepreciationAndAmortization</Role>
      <ShortName>COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2158100 - Disclosure - FINANCE EXPENSE, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinanceExpenseNet</Role>
      <ShortName>FINANCE EXPENSE, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2161100 - Disclosure - OTHER INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/OtherIncome</Role>
      <ShortName>OTHER INCOME</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2164100 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RelatedPartyTransactions</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2167100 - Disclosure - PRINCIPAL SUBSIDIARIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/PrincipalSubsidiaries</Role>
      <ShortName>PRINCIPAL SUBSIDIARIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2170100 - Disclosure - SEGMENTED INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SegmentedInformation</Role>
      <ShortName>SEGMENTED INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2173100 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SupplementalCashFlowInformation</Role>
      <ShortName>SUPPLEMENTAL CASH FLOW INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2176100 - Disclosure - FINANCIAL RISK MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialRiskManagement</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2179100 - Disclosure - CAPITAL RISK MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CapitalRiskManagement</Role>
      <ShortName>CAPITAL RISK MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2210201 - Disclosure - SUMMARY OF ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPoliciesPolicies</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsTables</Role>
      <ShortName>FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/FinancialInstruments</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - INVENTORIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/InventoriesTables</Role>
      <ShortName>INVENTORIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/Inventories</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2322301 - Disclosure - MINING INTERESTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/MiningInterestsTables</Role>
      <ShortName>MINING INTERESTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/MiningInterests</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2325301 - Disclosure - INCOME TAXES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesTables</Role>
      <ShortName>INCOME TAXES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/IncomeTaxes</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2328301 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/AccountsPayableAndAccruedLiabilitiesTables</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/AccountsPayableAndAccruedLiabilities</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2331301 - Disclosure - REHABILITATION PROVISIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RehabilitationProvisionsTables</Role>
      <ShortName>REHABILITATION PROVISIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/RehabilitationProvisions</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2334301 - Disclosure - DEFERRED REVENUE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DeferredRevenueTables</Role>
      <ShortName>DEFERRED REVENUE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/DeferredRevenue</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2337301 - Disclosure - DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DebtTables</Role>
      <ShortName>DEBT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/Debt</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2340301 - Disclosure - SHARE CAPITAL (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareCapitalTables</Role>
      <ShortName>SHARE CAPITAL (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/ShareCapital</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2343301 - Disclosure - COMMITMENTS AND CONTINGENCIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2346301 - Disclosure - SHARE-BASED COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationTables</Role>
      <ShortName>SHARE-BASED COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/ShareBasedCompensation</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2349301 - Disclosure - INCOME/(LOSS) PER COMMON SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeLossPerCommonShareTables</Role>
      <ShortName>INCOME/(LOSS) PER COMMON SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/IncomeLossPerCommonShare</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2352301 - Disclosure - REVENUE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RevenueTables</Role>
      <ShortName>REVENUE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/Revenue</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2355301 - Disclosure - COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CostOfSalesExcludingDepreciationAndAmortizationTables</Role>
      <ShortName>COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/CostOfSalesExcludingDepreciationAndAmortization</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2358301 - Disclosure - FINANCE EXPENSE, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinanceExpenseNetTables</Role>
      <ShortName>FINANCE EXPENSE, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/FinanceExpenseNet</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2361301 - Disclosure - OTHER INCOME (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/OtherIncomeTables</Role>
      <ShortName>OTHER INCOME (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/OtherIncome</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2364301 - Disclosure - RELATED PARTY TRANSACTIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RelatedPartyTransactionsTables</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/RelatedPartyTransactions</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2367301 - Disclosure - PRINCIPAL SUBSIDIARIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/PrincipalSubsidiariesTables</Role>
      <ShortName>PRINCIPAL SUBSIDIARIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/PrincipalSubsidiaries</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2370301 - Disclosure - SEGMENTED INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SegmentedInformationTables</Role>
      <ShortName>SEGMENTED INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/SegmentedInformation</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2373301 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SupplementalCashFlowInformationTables</Role>
      <ShortName>SUPPLEMENTAL CASH FLOW INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/SupplementalCashFlowInformation</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2376301 - Disclosure - FINANCIAL RISK MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialRiskManagementTables</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/FinancialRiskManagement</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2379301 - Disclosure - CAPITAL RISK MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CapitalRiskManagementTables</Role>
      <ShortName>CAPITAL RISK MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.gsr.com/role/CapitalRiskManagement</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - SUMMARY OF ACCOUNTING POLICIES - Property, plant and equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPoliciesPropertyPlantAndEquipmentDetails</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES - Property, plant and equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - SUMMARY OF ACCOUNTING POLICIES - Deferred revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPoliciesDeferredRevenueDetails</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES - Deferred revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - SUMMARY OF ACCOUNTING POLICIES - Share-based compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPoliciesShareBasedCompensationDetails</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES - Share-based compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2410405 - Disclosure - SUMMARY OF ACCOUNTING POLICIES - Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SummaryOfAccountingPoliciesFinancialInstrumentsDetails</Role>
      <ShortName>SUMMARY OF ACCOUNTING POLICIES - Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - FINANCIAL INSTRUMENTS - Fair value measurements for financial instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsFairValueMeasurementsForFinancialInstrumentsDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Fair value measurements for financial instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2416403 - Disclosure - FINANCIAL INSTRUMENTS - (Gain)/loss on fair value of financial instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsGainLossOnFairValueOfFinancialInstrumentsDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - (Gain)/loss on fair value of financial instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2416404 - Disclosure - FINANCIAL INSTRUMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsNarrativeDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2416405 - Disclosure - FINANCIAL INSTRUMENTS - Changes of financial liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsChangesOfFinancialLiabilitiesDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Changes of financial liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2416406 - Disclosure - FINANCIAL INSTRUMENTS - Fair Value Inputs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialInstrumentsFairValueInputsDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS - Fair Value Inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - INVENTORIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/InventoriesDetails</Role>
      <ShortName>INVENTORIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/InventoriesTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2422402 - Disclosure - MINING INTERESTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/MiningInterestsDetails</Role>
      <ShortName>MINING INTERESTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/MiningInterestsTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2425402 - Disclosure - INCOME TAXES - Schedule of Deferred Tax Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesScheduleOfDeferredTaxLiabilitiesDetails</Role>
      <ShortName>INCOME TAXES - Schedule of Deferred Tax Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2425403 - Disclosure - INCOME TAXES - Summary of Deferred Tax Asset Not Recognized (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesSummaryOfDeferredTaxAssetNotRecognizedDetails</Role>
      <ShortName>INCOME TAXES - Summary of Deferred Tax Asset Not Recognized (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2425404 - Disclosure - INCOME TAXES - Income Tax Recovery Components (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesIncomeTaxRecoveryComponentsDetails</Role>
      <ShortName>INCOME TAXES - Income Tax Recovery Components (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2425405 - Disclosure - INCOME TAXES - Income Tax Recovery Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesIncomeTaxRecoveryReconciliationDetails</Role>
      <ShortName>INCOME TAXES - Income Tax Recovery Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2425406 - Disclosure - INCOME TAXES - Schedule Of Tax Pool And Loss Carryover Expiration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeTaxesScheduleOfTaxPoolAndLossCarryoverExpirationDetails</Role>
      <ShortName>INCOME TAXES - Schedule Of Tax Pool And Loss Carryover Expiration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2428402 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/AccountsPayableAndAccruedLiabilitiesDetails</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/AccountsPayableAndAccruedLiabilitiesTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>2431402 - Disclosure - REHABILITATION PROVISIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RehabilitationProvisionsDetails</Role>
      <ShortName>REHABILITATION PROVISIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/RehabilitationProvisionsTables</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>2434402 - Disclosure - DEFERRED REVENUE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DeferredRevenueDetails</Role>
      <ShortName>DEFERRED REVENUE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/DeferredRevenueTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>2437402 - Disclosure - DEBT - Schedule of Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DebtScheduleOfDebtDetails</Role>
      <ShortName>DEBT - Schedule of Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>2437403 - Disclosure - DEBT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DebtNarrativeDetails</Role>
      <ShortName>DEBT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>2437404 - Disclosure - DEBT - Schedule of changes in carrying amount of debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DebtScheduleOfChangesInCarryingAmountOfDebtDetails</Role>
      <ShortName>DEBT - Schedule of changes in carrying amount of debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>2437405 - Disclosure - DEBT - Schedule of payments on outstanding debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/DebtScheduleOfPaymentsOnOutstandingDebtDetails</Role>
      <ShortName>DEBT - Schedule of payments on outstanding debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>2440402 - Disclosure - SHARE CAPITAL (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareCapitalDetails</Role>
      <ShortName>SHARE CAPITAL (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/ShareCapitalTables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>2443402 - Disclosure - COMMITMENTS AND CONTINGENCIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CommitmentsAndContingenciesNarrativeDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>2443403 - Disclosure - COMMITMENTS AND CONTINGENCIES - Operating Leases and Capital Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CommitmentsAndContingenciesOperatingLeasesAndCapitalCommitmentsDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Operating Leases and Capital Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>2446402 - Disclosure - SHARE-BASED COMPENSATION - Employee compensation expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationEmployeeCompensationExpenseDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Employee compensation expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>2446403 - Disclosure - SHARE-BASED COMPENSATION - Fair value assumptions for share options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationFairValueAssumptionsForShareOptionsDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Fair value assumptions for share options (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>2446404 - Disclosure - SHARE-BASED COMPENSATION - Additional information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationAdditionalInformationDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Additional information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>2446405 - Disclosure - SHARE-BASED COMPENSATION - Summary of option activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationSummaryOfOptionActivityDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Summary of option activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>2446406 - Disclosure - SHARE-BASED COMPENSATION - Number of options outstanding by strike price (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationNumberOfOptionsOutstandingByStrikePriceDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Number of options outstanding by strike price (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>2446407 - Disclosure - SHARE-BASED COMPENSATION - Summary of DSU activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationSummaryOfDsuActivityDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Summary of DSU activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>2446408 - Disclosure - SHARE-BASED COMPENSATION - Summary of SAR activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationSummaryOfSarActivityDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Summary of SAR activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>2446409 - Disclosure - SHARE-BASED COMPENSATION - Summary of PSU activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/ShareBasedCompensationSummaryOfPsuActivityDetails</Role>
      <ShortName>SHARE-BASED COMPENSATION - Summary of PSU activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>2449402 - Disclosure - INCOME/(LOSS) PER COMMON SHARE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/IncomeLossPerCommonShareDetails</Role>
      <ShortName>INCOME/(LOSS) PER COMMON SHARE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/IncomeLossPerCommonShareTables</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>2452402 - Disclosure - REVENUE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RevenueDetails</Role>
      <ShortName>REVENUE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/RevenueTables</ParentRole>
      <Position>93</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>2455402 - Disclosure - COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CostOfSalesExcludingDepreciationAndAmortizationDetails</Role>
      <ShortName>COST OF SALES EXCLUDING DEPRECIATION AND AMORTIZATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/CostOfSalesExcludingDepreciationAndAmortizationTables</ParentRole>
      <Position>94</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>2458402 - Disclosure - FINANCE EXPENSE, NET (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinanceExpenseNetDetails</Role>
      <ShortName>FINANCE EXPENSE, NET (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/FinanceExpenseNetTables</ParentRole>
      <Position>95</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>2461402 - Disclosure - OTHER INCOME (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/OtherIncomeDetails</Role>
      <ShortName>OTHER INCOME (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/OtherIncomeTables</ParentRole>
      <Position>96</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>2464402 - Disclosure - RELATED PARTY TRANSACTIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/RelatedPartyTransactionsDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/RelatedPartyTransactionsTables</ParentRole>
      <Position>97</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>2467402 - Disclosure - PRINCIPAL SUBSIDIARIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/PrincipalSubsidiariesDetails</Role>
      <ShortName>PRINCIPAL SUBSIDIARIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/PrincipalSubsidiariesTables</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>2470402 - Disclosure - SEGMENTED INFORMATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SegmentedInformationDetails</Role>
      <ShortName>SEGMENTED INFORMATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/SegmentedInformationTables</ParentRole>
      <Position>99</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>2473402 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SupplementalCashFlowInformationNarrativeDetails</Role>
      <ShortName>SUPPLEMENTAL CASH FLOW INFORMATION - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>2473403 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Changes in Working Capital (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SupplementalCashFlowInformationChangesInWorkingCapitalDetails</Role>
      <ShortName>SUPPLEMENTAL CASH FLOW INFORMATION - Changes in Working Capital (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>2473404 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Reconciliation of Other Components (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/SupplementalCashFlowInformationReconciliationOfOtherComponentsDetails</Role>
      <ShortName>SUPPLEMENTAL CASH FLOW INFORMATION - Reconciliation of Other Components (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>2476402 - Disclosure - FINANCIAL RISK MANAGEMENT - Schedule of Contractual Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialRiskManagementScheduleOfContractualObligationsDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Schedule of Contractual Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>2476403 - Disclosure - FINANCIAL RISK MANAGEMENT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/FinancialRiskManagementNarrativeDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="gss-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>2479402 - Disclosure - CAPITAL RISK MANAGEMENT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.gsr.com/role/CapitalRiskManagementDetails</Role>
      <ShortName>CAPITAL RISK MANAGEMENT (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.gsr.com/role/CapitalRiskManagementTables</ParentRole>
      <Position>105</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>gss-20171231.xml</File>
    <File>gss-20171231.xsd</File>
    <File>gss-20171231_cal.xml</File>
    <File>gss-20171231_def.xml</File>
    <File>gss-20171231_lab.xml</File>
    <File>gss-20171231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2017-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/invest/2013-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2014-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.ifrs.org/taxonomy/2017-03-09/ifrs-full</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
