<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>908</ContextCount>
  <ElementCount>724</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>243</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>8</UnitCount>
  <MyReports>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>1001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1002 - Statement - CONSOLIDATED STATEMENTS OF FINANCIAL POSITION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfFinancialPosition</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF FINANCIAL POSITION</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1003 - Statement - CONSOLIDATED  STATEMENTS OF PROFIT OR LOSS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfProfitOrLoss</Role>
      <ShortName>CONSOLIDATED  STATEMENTS OF PROFIT OR LOSS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1004 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1005 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfChangesInEquity</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1006 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1007 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS 1</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfCashFlows1</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS 1</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1008 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS 1(Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ConsolidatedStatementsOfCashFlows1Parenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS 1(Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1009 - Disclosure - GENERAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/General</Role>
      <ShortName>GENERAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1010 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SignificantAccountingPolicies</Role>
      <ShortName>SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1011 - Disclosure - CRITICAL ACCOUNTING JUDGEMENTS AND KEY SOURCES OF ESTIMATION UNCERTAINTY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CriticalAccountingJudgementsAndKeySourcesOfEstimationUncertainty</Role>
      <ShortName>CRITICAL ACCOUNTING JUDGEMENTS AND KEY SOURCES OF ESTIMATION UNCERTAINTY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1012 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagement</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>1013 - Disclosure - RELATED PARTIES TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RelatedPartiesTransactions</Role>
      <ShortName>RELATED PARTIES TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>1014 - Disclosure - CASH AND BANK BALANCES INCLUDING RESTRICTED CASH.</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CashAndBankBalancesIncludingRestrictedCash</Role>
      <ShortName>CASH AND BANK BALANCES INCLUDING RESTRICTED CASH.</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>1015 - Disclosure - TRADE RECEIVABLES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivables</Role>
      <ShortName>TRADE RECEIVABLES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>1016 - Disclosure - CONTRACT ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ContractAssets</Role>
      <ShortName>CONTRACT ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>1017 - Disclosure - OTHER RECEIVABLES AND PREPAYMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherReceivablesAndPrepayments</Role>
      <ShortName>OTHER RECEIVABLES AND PREPAYMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>1018 - Disclosure - LOANS TO JOINT VENTURES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LoansToJointVentures</Role>
      <ShortName>LOANS TO JOINT VENTURES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>1019 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstruments</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>1020 - Disclosure - INVENTORIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Inventories</Role>
      <ShortName>INVENTORIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>1021 - Disclosure - SHIPS, PROPERTY, PLANT AND EQUIPMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipment</Role>
      <ShortName>SHIPS, PROPERTY, PLANT AND EQUIPMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>1022 - Disclosure - RIGHT-OF-USE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RightOfUseAssets</Role>
      <ShortName>RIGHT-OF-USE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>1023 - Disclosure - SUBSIDIARIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Subsidiaries</Role>
      <ShortName>SUBSIDIARIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>1024 - Disclosure - INTEREST IN JOINT VENTURES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestInJointVentures</Role>
      <ShortName>INTEREST IN JOINT VENTURES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>1025 - Disclosure - INTANGIBLE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IntangibleAssets</Role>
      <ShortName>INTANGIBLE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>1026 - Disclosure - GOODWILL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Goodwill</Role>
      <ShortName>GOODWILL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>1027 - Disclosure - OTHER INVESTMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherInvestments</Role>
      <ShortName>OTHER INVESTMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>1028 - Disclosure - DEFERRED TAX</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DeferredTax</Role>
      <ShortName>DEFERRED TAX</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>1029 - Disclosure - TRADE AND OTHER PAYABLES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeAndOtherPayables</Role>
      <ShortName>TRADE AND OTHER PAYABLES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>1030 - Disclosure - CONTRACT LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ContractLiabilities</Role>
      <ShortName>CONTRACT LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>1031 - Disclosure - LEASES AND SHIP CHARTERS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeasesAndShipCharters</Role>
      <ShortName>LEASES AND SHIP CHARTERS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>1032 - Disclosure - LEASE LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeaseLiabilities</Role>
      <ShortName>LEASE LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>1033 - Disclosure - BANK LOANS AND OTHER BORROWINGS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/BankLoansAndOtherBorrowings</Role>
      <ShortName>BANK LOANS AND OTHER BORROWINGS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>1034 - Disclosure - PROVISIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Provisions</Role>
      <ShortName>PROVISIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>1035 - Disclosure - RETIREMENT BENEFIT OBLIGATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligation</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>1036 - Disclosure - SHARE CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShareCapital</Role>
      <ShortName>SHARE CAPITAL</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>1037 - Disclosure - OTHER EQUITY AND RESERVES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReserves</Role>
      <ShortName>OTHER EQUITY AND RESERVES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>1038 - Disclosure - REVENUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Revenue</Role>
      <ShortName>REVENUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>1039 - Disclosure - SEGMENT INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SegmentInformation</Role>
      <ShortName>SEGMENT INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>1040 - Disclosure - OTHER OPERATING INCOME (EXPENSE)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherOperatingIncomeExpense</Role>
      <ShortName>OTHER OPERATING INCOME (EXPENSE)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>1041 - Disclosure - INTEREST INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestIncome</Role>
      <ShortName>INTEREST INCOME</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>1042 - Disclosure - INTEREST EXPENSE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestExpense</Role>
      <ShortName>INTEREST EXPENSE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>1043 - Disclosure -  PROFIT (LOSS) BEFORE TAXATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ProfitLossBeforeTaxation</Role>
      <ShortName>PROFIT (LOSS) BEFORE TAXATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>1044 - Disclosure - INCOME TAX</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IncomeTax</Role>
      <ShortName>INCOME TAX</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>1045 - Disclosure - DISCONTINUED OPERATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DiscontinuedOperation</Role>
      <ShortName>DISCONTINUED OPERATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>1046 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSale</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>1047 - Disclosure - ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinesses</Role>
      <ShortName>ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>1048 - Disclosure - EARNINGS PER SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShare</Role>
      <ShortName>EARNINGS PER SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>1049 - Disclosure - DIVIDENDS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Dividends</Role>
      <ShortName>DIVIDENDS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>1050 - Disclosure - NON-CONTROLLING INTEREST</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/NonControllingInterest</Role>
      <ShortName>NON-CONTROLLING INTEREST</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>1051 - Disclosure - COMMITMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/Commitments</Role>
      <ShortName>COMMITMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>1052 - Disclosure - GOING CONCERN</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/GoingConcern</Role>
      <ShortName>GOING CONCERN</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>1053 - Disclosure - EVENTS AFTER THE REPORTING PERIOD</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EventsAfterTheReportingPeriod</Role>
      <ShortName>EVENTS AFTER THE REPORTING PERIOD</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>1054 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SignificantAccountingPoliciesPolicies</Role>
      <ShortName>SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>1055 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SignificantAccountingPoliciesTables</Role>
      <ShortName>SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SignificantAccountingPolicies</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>1056 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagement</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>1057 - Disclosure - RELATED PARTIES TRANSACTIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RelatedPartiesTransactionsTables</Role>
      <ShortName>RELATED PARTIES TRANSACTIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RelatedPartiesTransactions</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>1058 - Disclosure - CASH AND BANK BALANCES INCLUDING RESTRICTED CASH (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CashAndBankBalancesIncludingRestrictedCashTables</Role>
      <ShortName>CASH AND BANK BALANCES INCLUDING RESTRICTED CASH (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/CashAndBankBalancesIncludingRestrictedCash</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>1059 - Disclosure - TRADE RECEIVABLES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesTables</Role>
      <ShortName>TRADE RECEIVABLES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>1060 - Disclosure - OTHER RECEIVABLES AND PREPAYMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherReceivablesAndPrepaymentsTables</Role>
      <ShortName>OTHER RECEIVABLES AND PREPAYMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherReceivablesAndPrepayments</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>1061 - Disclosure - LOANS TO JOINT VENTURES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LoansToJointVenturesTables</Role>
      <ShortName>LOANS TO JOINT VENTURES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LoansToJointVentures</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>1062 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsTables</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DerivativeFinancialInstruments</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>1063 - Disclosure - INVENTORIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InventoriesTables</Role>
      <ShortName>INVENTORIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Inventories</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>1064 - Disclosure - SHIPS, PROPERTY, PLANT AND EQUIPMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipmentTables</Role>
      <ShortName>SHIPS, PROPERTY, PLANT AND EQUIPMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipment</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>1065 - Disclosure - RIGHT-OF-USE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RightOfUseAssetsTables</Role>
      <ShortName>RIGHT-OF-USE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RightOfUseAssets</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>1066 - Disclosure - SUBSIDIARIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SubsidiariesTables</Role>
      <ShortName>SUBSIDIARIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Subsidiaries</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>1067 - Disclosure - INTEREST IN JOINT VENTURES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestInJointVenturesTables</Role>
      <ShortName>INTEREST IN JOINT VENTURES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestInJointVentures</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>1068 - Disclosure - INTANGIBLE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IntangibleAssetsTables</Role>
      <ShortName>INTANGIBLE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IntangibleAssets</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>1069 - Disclosure - GOODWILL (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/GoodwillTables</Role>
      <ShortName>GOODWILL (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Goodwill</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>1070 - Disclosure - OTHER INVESTMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherInvestmentsTables</Role>
      <ShortName>OTHER INVESTMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherInvestments</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>1071 - Disclosure - DEFERRED TAX (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DeferredTaxTables</Role>
      <ShortName>DEFERRED TAX (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DeferredTax</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>1072 - Disclosure - TRADE AND OTHER PAYABLES  (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeAndOtherPayablesTables</Role>
      <ShortName>TRADE AND OTHER PAYABLES  (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeAndOtherPayables</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>1073 - Disclosure - LEASES AND SHIP CHARTERS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeasesAndShipChartersTables</Role>
      <ShortName>LEASES AND SHIP CHARTERS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeasesAndShipCharters</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>1074 - Disclosure - LEASE LIABILITIES (Table)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeaseLiabilitiesTable</Role>
      <ShortName>LEASE LIABILITIES (Table)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeaseLiabilities</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>1075 - Disclosure - BANK LOANS AND OTHER BORROWINGS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/BankLoansAndOtherBorrowingsTables</Role>
      <ShortName>BANK LOANS AND OTHER BORROWINGS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/BankLoansAndOtherBorrowings</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>1076 - Disclosure - PROVISIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ProvisionsTables</Role>
      <ShortName>PROVISIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Provisions</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>1077 - Disclosure - RETIREMENT BENEFIT OBLIGATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligationTables</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RetirementBenefitObligation</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>1078 - Disclosure - SHARE CAPITAL (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShareCapitalTables</Role>
      <ShortName>SHARE CAPITAL (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShareCapital</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>1079 - Disclosure - OTHER EQUITY AND RESERVES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesTables</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReserves</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>1080 - Disclosure - REVENUE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RevenueTables</Role>
      <ShortName>REVENUE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Revenue</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>1081 - Disclosure - SEGMENT INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SegmentInformationTables</Role>
      <ShortName>SEGMENT INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SegmentInformation</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>1082 - Disclosure - OTHER OPERATING INCOME (EXPENSE) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherOperatingIncomeExpenseTables</Role>
      <ShortName>OTHER OPERATING INCOME (EXPENSE) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherOperatingIncomeExpense</ParentRole>
      <Position>82</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>1083 - Disclosure - INTEREST INCOME (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestIncomeTables</Role>
      <ShortName>INTEREST INCOME (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestIncome</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>1084 - Disclosure - INTEREST EXPENSE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestExpenseTables</Role>
      <ShortName>INTEREST EXPENSE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestExpense</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>1085 - Disclosure -  PROFIT (LOSS) BEFORE TAXATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ProfitLossBeforeTaxationTables</Role>
      <ShortName>PROFIT (LOSS) BEFORE TAXATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ProfitLossBeforeTaxation</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>1086 - Disclosure - INCOME TAX (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IncomeTaxTables</Role>
      <ShortName>INCOME TAX (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IncomeTax</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>1087 - Disclosure - DISCONTINUED OPERATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DiscontinuedOperationTables</Role>
      <ShortName>DISCONTINUED OPERATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DiscontinuedOperation</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>1088 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleTables</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSale</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>1089 - Disclosure - ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinessesTables</Role>
      <ShortName>ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinesses</ParentRole>
      <Position>89</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>1090 - Disclosure - EARNINGS PER SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShareTables</Role>
      <ShortName>EARNINGS PER SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EarningsPerShare</ParentRole>
      <Position>90</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>1091 - Disclosure - DIVIDENDS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DividendsTables</Role>
      <ShortName>DIVIDENDS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Dividends</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>1092 - Disclosure - NON-CONTROLLING INTEREST (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/NonControllingInterestTables</Role>
      <ShortName>NON-CONTROLLING INTEREST (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/NonControllingInterest</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>1093 - Disclosure - COMMITMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CommitmentsTables</Role>
      <ShortName>COMMITMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/Commitments</ParentRole>
      <Position>93</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>1094 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SignificantAccountingPoliciesDetails2</Role>
      <ShortName>SIGNIFICANT ACCOUNTING POLICIES (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SignificantAccountingPoliciesTables</ParentRole>
      <Position>94</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>1095 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SignificantAccountingPoliciesDetailsTextual</Role>
      <ShortName>SIGNIFICANT ACCOUNTING POLICIES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SignificantAccountingPoliciesTables</ParentRole>
      <Position>95</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>1096 - Disclosure - CRITICAL ACCOUNTING JUDGEMENTS AND KEY SOURCES OF ESTIMATION UNCERTAINTY (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CriticalAccountingJudgementsAndKeySourcesOfEstimationUncertaintyDetailsTextual</Role>
      <ShortName>CRITICAL ACCOUNTING JUDGEMENTS AND KEY SOURCES OF ESTIMATION UNCERTAINTY (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/CriticalAccountingJudgementsAndKeySourcesOfEstimationUncertainty</ParentRole>
      <Position>96</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>1097 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>97</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>1098 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails1</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>1099 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails2</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>99</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>1100 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails3</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>100</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>1101 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails5</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>101</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>1102 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 6)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails6</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 6)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>102</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>1103 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 7)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails7</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 7)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>103</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>1104 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 8)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetails8</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details 8)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>104</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>1105 - Disclosure - FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementDetailsTextual</Role>
      <ShortName>FINANCIAL INSTRUMENTS, FINANCIAL RISKS AND CAPITAL MANAGEMENT (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/FinancialInstrumentsFinancialRisksAndCapitalManagementTables</ParentRole>
      <Position>105</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>1106 - Disclosure - RELATED PARTIES TRANSACTIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RelatedPartiesTransactionsDetails</Role>
      <ShortName>RELATED PARTIES TRANSACTIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RelatedPartiesTransactionsTables</ParentRole>
      <Position>106</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>1107 - Disclosure - RELATED PARTIES TRANSACTIONS (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RelatedPartiesTransactionsDetails1</Role>
      <ShortName>RELATED PARTIES TRANSACTIONS (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RelatedPartiesTransactionsTables</ParentRole>
      <Position>107</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>1108 - Disclosure - CASH AND BANK BALANCES INCLUDING RESTRICTED CASH (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CashAndBankBalancesIncludingRestrictedCashDetails</Role>
      <ShortName>CASH AND BANK BALANCES INCLUDING RESTRICTED CASH (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/CashAndBankBalancesIncludingRestrictedCashTables</ParentRole>
      <Position>108</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>1109 - Disclosure - TRADE RECEIVABLES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesDetails</Role>
      <ShortName>TRADE RECEIVABLES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivablesTables</ParentRole>
      <Position>109</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>1110 - Disclosure - TRADE RECEIVABLES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesDetails1</Role>
      <ShortName>TRADE RECEIVABLES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivablesTables</ParentRole>
      <Position>110</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>1111 - Disclosure - TRADE RECEIVABLES (Details 4)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesDetails4</Role>
      <ShortName>TRADE RECEIVABLES (Details 4)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivablesTables</ParentRole>
      <Position>111</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>1112 - Disclosure - TRADE RECEIVABLES (Details 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesDetails5</Role>
      <ShortName>TRADE RECEIVABLES (Details 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivablesTables</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>1113 - Disclosure - TRADE RECEIVABLES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeReceivablesDetailsTextual</Role>
      <ShortName>TRADE RECEIVABLES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeReceivablesTables</ParentRole>
      <Position>113</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>1114 - Disclosure - CONTRACT ASSETS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ContractAssetsDetailsTextual</Role>
      <ShortName>CONTRACT ASSETS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ContractAssets</ParentRole>
      <Position>114</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>1115 - Disclosure - OTHER RECEIVABLES AND PREPAYMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherReceivablesAndPrepaymentsDetails</Role>
      <ShortName>OTHER RECEIVABLES AND PREPAYMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherReceivablesAndPrepaymentsTables</ParentRole>
      <Position>115</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>1116 - Disclosure - OTHER RECEIVABLES AND PREPAYMENTS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherReceivablesAndPrepaymentsDetailsTextual</Role>
      <ShortName>OTHER RECEIVABLES AND PREPAYMENTS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherReceivablesAndPrepaymentsTables</ParentRole>
      <Position>116</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>1117 - Disclosure - LOANS TO JOINT VENTURES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LoansToJointVenturesDetails</Role>
      <ShortName>LOANS TO JOINT VENTURES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LoansToJointVenturesTables</ParentRole>
      <Position>117</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>1118 - Disclosure - LOANS TO JOINT VENTURES (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LoansToJointVenturesParentheticalDetails</Role>
      <ShortName>LOANS TO JOINT VENTURES (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LoansToJointVenturesTables</ParentRole>
      <Position>118</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>1119 - Disclosure - LOANS TO JOINT VENTURES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LoansToJointVenturesDetails1</Role>
      <ShortName>LOANS TO JOINT VENTURES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LoansToJointVenturesTables</ParentRole>
      <Position>119</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>1120 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsDetails</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsTables</ParentRole>
      <Position>120</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>1121 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsDetails1</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsTables</ParentRole>
      <Position>121</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>1122 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsDetails2</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsTables</ParentRole>
      <Position>122</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>1123 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsDetailsTextual</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DerivativeFinancialInstrumentsTables</ParentRole>
      <Position>123</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>1124 - Disclosure - INVENTORIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InventoriesDetails</Role>
      <ShortName>INVENTORIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InventoriesTables</ParentRole>
      <Position>124</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>1125 - Disclosure - INVENTORIES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InventoriesDetails1</Role>
      <ShortName>INVENTORIES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InventoriesTables</ParentRole>
      <Position>125</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>1126 - Disclosure - INVENTORIES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InventoriesDetailsTextual</Role>
      <ShortName>INVENTORIES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InventoriesTables</ParentRole>
      <Position>126</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>1127 - Disclosure - SHIPS, PROPERTY, PLANT AND EQUIPMENT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipmentDetails</Role>
      <ShortName>SHIPS, PROPERTY, PLANT AND EQUIPMENT (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipmentTables</ParentRole>
      <Position>127</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>1128 - Disclosure - SHIPS, PROPERTY, PLANT AND EQUIPMENT (Details textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipmentDetailsTextual</Role>
      <ShortName>SHIPS, PROPERTY, PLANT AND EQUIPMENT (Details textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShipsPropertyPlantAndEquipmentTables</ParentRole>
      <Position>128</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>1129 - Disclosure - RIGHT-OF-USE ASSETS - Summary of group leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RightOfUseAssetsSummaryOfGroupLeasesDetail</Role>
      <ShortName>RIGHT-OF-USE ASSETS - Summary of group leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>129</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>1130 - Disclosure - RIGHT-OF-USE ASSETS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RightOfUseAssetsDetailsTextual</Role>
      <ShortName>RIGHT-OF-USE ASSETS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RightOfUseAssetsTables</ParentRole>
      <Position>130</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>1131 - Disclosure - SUBSIDIARIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SubsidiariesDetails</Role>
      <ShortName>SUBSIDIARIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SubsidiariesTables</ParentRole>
      <Position>131</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>1132 - Disclosure - SUBSIDIARIES (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SubsidiariesParentheticalDetails</Role>
      <ShortName>SUBSIDIARIES (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SubsidiariesTables</ParentRole>
      <Position>132</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>1133 - Disclosure - INTEREST IN JOINT VENTURES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestInJointVenturesDetails</Role>
      <ShortName>INTEREST IN JOINT VENTURES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestInJointVenturesTables</ParentRole>
      <Position>133</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>1134 - Disclosure - INTEREST IN JOINT VENTURES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestInJointVenturesDetails1</Role>
      <ShortName>INTEREST IN JOINT VENTURES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestInJointVenturesTables</ParentRole>
      <Position>134</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>1135 - Disclosure - INTEREST IN JOINT VENTURES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestInJointVenturesDetailsTextual</Role>
      <ShortName>INTEREST IN JOINT VENTURES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestInJointVenturesTables</ParentRole>
      <Position>135</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>1136 - Disclosure - INTANGIBLE ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IntangibleAssetsDetails</Role>
      <ShortName>INTANGIBLE ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IntangibleAssetsTables</ParentRole>
      <Position>136</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>1137 - Disclosure - INTANGIBLE ASSETS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IntangibleAssetsDetailsTextual</Role>
      <ShortName>INTANGIBLE ASSETS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IntangibleAssetsTables</ParentRole>
      <Position>137</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>1138 - Disclosure - GOODWILL (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/GoodwillDetails</Role>
      <ShortName>GOODWILL (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/GoodwillTables</ParentRole>
      <Position>138</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>1139 - Disclosure - GOODWILL (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/GoodwillDetails1</Role>
      <ShortName>GOODWILL (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/GoodwillTables</ParentRole>
      <Position>139</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>1140 - Disclosure - GOODWILL (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/GoodwillDetailsTextual</Role>
      <ShortName>GOODWILL (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/GoodwillTables</ParentRole>
      <Position>140</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>1141 - Disclosure - OTHER INVESTMENTS (Parenthetical) (Detail 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherInvestmentsParentheticalDetail1</Role>
      <ShortName>OTHER INVESTMENTS (Parenthetical) (Detail 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherInvestmentsTables</ParentRole>
      <Position>141</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>1142 - Disclosure - OTHER INVESTMENTS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherInvestmentsDetailsTextual</Role>
      <ShortName>OTHER INVESTMENTS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherInvestmentsTables</ParentRole>
      <Position>142</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>1143 - Disclosure - OTHER INVESTMENTS (Detail 5)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherInvestmentsDetail5</Role>
      <ShortName>OTHER INVESTMENTS (Detail 5)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherInvestmentsTables</ParentRole>
      <Position>143</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>1144 - Disclosure - DEFERRED TAX (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DeferredTaxDetails</Role>
      <ShortName>DEFERRED TAX (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DeferredTaxTables</ParentRole>
      <Position>144</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>1145 - Disclosure - DEFERRED TAX (Detail Textuals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DeferredTaxDetailTextuals</Role>
      <ShortName>DEFERRED TAX (Detail Textuals)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DeferredTaxTables</ParentRole>
      <Position>145</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>1146 - Disclosure - TRADE AND OTHER PAYABLES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/TradeAndOtherPayablesDetails</Role>
      <ShortName>TRADE AND OTHER PAYABLES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/TradeAndOtherPayablesTables</ParentRole>
      <Position>146</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>1147 - Disclosure - LEASES AND SHIP CHARTERS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeasesAndShipChartersDetails</Role>
      <ShortName>LEASES AND SHIP CHARTERS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeasesAndShipChartersTables</ParentRole>
      <Position>147</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R148.htm</HtmlFileName>
      <LongName>1148 - Disclosure - LEASES AND SHIP CHARTERS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeasesAndShipChartersDetailsTextual</Role>
      <ShortName>LEASES AND SHIP CHARTERS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeasesAndShipChartersTables</ParentRole>
      <Position>148</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R149.htm</HtmlFileName>
      <LongName>1149 - Disclosure - LEASE LIABILITIES - (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeaseLiabilitiesDetails</Role>
      <ShortName>LEASE LIABILITIES - (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeaseLiabilitiesTable</ParentRole>
      <Position>149</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R150.htm</HtmlFileName>
      <LongName>1150 - Disclosure - LEASE LIABILITIES - (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeaseLiabilitiesDetails1</Role>
      <ShortName>LEASE LIABILITIES - (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeaseLiabilitiesTable</ParentRole>
      <Position>150</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R151.htm</HtmlFileName>
      <LongName>1151 - Disclosure - LEASE LIABILITIES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/LeaseLiabilitiesDetailsTextual</Role>
      <ShortName>LEASE LIABILITIES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/LeaseLiabilitiesTable</ParentRole>
      <Position>151</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R152.htm</HtmlFileName>
      <LongName>1152 - Disclosure - BANK LOANS AND OTHER BORROWINGS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/BankLoansAndOtherBorrowingsDetails</Role>
      <ShortName>BANK LOANS AND OTHER BORROWINGS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/BankLoansAndOtherBorrowingsTables</ParentRole>
      <Position>152</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R153.htm</HtmlFileName>
      <LongName>1153 - Disclosure - BANK LOANS AND OTHER BORROWINGS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/BankLoansAndOtherBorrowingsDetailsTextual</Role>
      <ShortName>BANK LOANS AND OTHER BORROWINGS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/BankLoansAndOtherBorrowingsTables</ParentRole>
      <Position>153</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R154.htm</HtmlFileName>
      <LongName>1154 - Disclosure - PROVISIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ProvisionsDetails</Role>
      <ShortName>PROVISIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ProvisionsTables</ParentRole>
      <Position>154</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R155.htm</HtmlFileName>
      <LongName>1155 - Disclosure - PROVISIONS (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ProvisionsDetails1</Role>
      <ShortName>PROVISIONS (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ProvisionsTables</ParentRole>
      <Position>155</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R156.htm</HtmlFileName>
      <LongName>1156 - Disclosure - RETIREMENT BENEFIT OBLIGATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligationDetails</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RetirementBenefitObligationTables</ParentRole>
      <Position>156</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R157.htm</HtmlFileName>
      <LongName>1157 - Disclosure - RETIREMENT BENEFIT OBLIGATION (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligationDetails1</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RetirementBenefitObligationTables</ParentRole>
      <Position>157</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R158.htm</HtmlFileName>
      <LongName>1158 - Disclosure - RETIREMENT BENEFIT OBLIGATION (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligationDetails2</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RetirementBenefitObligationTables</ParentRole>
      <Position>158</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R159.htm</HtmlFileName>
      <LongName>1159 - Disclosure - RETIREMENT BENEFIT OBLIGATION (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RetirementBenefitObligationDetailsTextual</Role>
      <ShortName>RETIREMENT BENEFIT OBLIGATION (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RetirementBenefitObligationTables</ParentRole>
      <Position>159</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R160.htm</HtmlFileName>
      <LongName>1160 - Disclosure - SHARE CAPITAL  (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShareCapitalDetails</Role>
      <ShortName>SHARE CAPITAL  (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShareCapitalTables</ParentRole>
      <Position>160</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R161.htm</HtmlFileName>
      <LongName>1161 - Disclosure - SHARE CAPITAL (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/ShareCapitalDetailsTextual</Role>
      <ShortName>SHARE CAPITAL (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/ShareCapitalTables</ParentRole>
      <Position>161</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R162.htm</HtmlFileName>
      <LongName>1162 - Disclosure - OTHER EQUITY AND RESERVES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesDetails</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReservesTables</ParentRole>
      <Position>162</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R163.htm</HtmlFileName>
      <LongName>1163 - Disclosure - OTHER EQUITY AND RESERVES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesDetails1</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReservesTables</ParentRole>
      <Position>163</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R164.htm</HtmlFileName>
      <LongName>1164 - Disclosure - OTHER EQUITY AND RESERVES (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesDetails2</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Details 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReservesTables</ParentRole>
      <Position>164</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R165.htm</HtmlFileName>
      <LongName>1165 - Disclosure - OTHER EQUITY AND RESERVES (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesDetails3</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReservesTables</ParentRole>
      <Position>165</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R166.htm</HtmlFileName>
      <LongName>1166 - Disclosure - OTHER EQUITY AND RESERVES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherEquityAndReservesDetailsTextual</Role>
      <ShortName>OTHER EQUITY AND RESERVES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherEquityAndReservesTables</ParentRole>
      <Position>166</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R167.htm</HtmlFileName>
      <LongName>1167 - Disclosure - REVENUE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RevenueDetails</Role>
      <ShortName>REVENUE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RevenueTables</ParentRole>
      <Position>167</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R168.htm</HtmlFileName>
      <LongName>1168 - Disclosure - REVENUE (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/RevenueDetailsTextual</Role>
      <ShortName>REVENUE (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/RevenueTables</ParentRole>
      <Position>168</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R169.htm</HtmlFileName>
      <LongName>1169 - Disclosure - SEGMENT INFORMATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SegmentInformationDetails</Role>
      <ShortName>SEGMENT INFORMATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SegmentInformationTables</ParentRole>
      <Position>169</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R170.htm</HtmlFileName>
      <LongName>1170 - Disclosure - SEGMENT INFORMATION (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/SegmentInformationDetailsTextual</Role>
      <ShortName>SEGMENT INFORMATION (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/SegmentInformationTables</ParentRole>
      <Position>170</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R171.htm</HtmlFileName>
      <LongName>1171 - Disclosure - OTHER OPERATING INCOME (EXPENSE) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/OtherOperatingIncomeExpenseDetails</Role>
      <ShortName>OTHER OPERATING INCOME (EXPENSE) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/OtherOperatingIncomeExpenseTables</ParentRole>
      <Position>171</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R172.htm</HtmlFileName>
      <LongName>1172 - Disclosure - INTEREST INCOME (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestIncomeDetails</Role>
      <ShortName>INTEREST INCOME (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestIncomeTables</ParentRole>
      <Position>172</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R173.htm</HtmlFileName>
      <LongName>1173 - Disclosure - INTEREST EXPENSE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/InterestExpenseDetails</Role>
      <ShortName>INTEREST EXPENSE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/InterestExpenseTables</ParentRole>
      <Position>173</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R174.htm</HtmlFileName>
      <LongName>1174 - Disclosure - PEOFIT (LOSS) BEFORE TAXATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/PeofitLossBeforeTaxationDetails</Role>
      <ShortName>PEOFIT (LOSS) BEFORE TAXATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>174</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R175.htm</HtmlFileName>
      <LongName>1175 - Disclosure - INCOME TAX (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IncomeTaxDetails</Role>
      <ShortName>INCOME TAX (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IncomeTaxTables</ParentRole>
      <Position>175</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R176.htm</HtmlFileName>
      <LongName>1176 - Disclosure - INCOME TAX (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IncomeTaxDetails1</Role>
      <ShortName>INCOME TAX (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IncomeTaxTables</ParentRole>
      <Position>176</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R177.htm</HtmlFileName>
      <LongName>1177 - Disclosure - INCOME TAX (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/IncomeTaxDetailsTextual</Role>
      <ShortName>INCOME TAX (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/IncomeTaxTables</ParentRole>
      <Position>177</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R178.htm</HtmlFileName>
      <LongName>1178 - Disclosure - DISCONTINUED OPERATION (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DiscontinuedOperationDetail</Role>
      <ShortName>DISCONTINUED OPERATION (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DiscontinuedOperationTables</ParentRole>
      <Position>178</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R179.htm</HtmlFileName>
      <LongName>1179 - Disclosure - DISCONTINUED OPERATION (Detail 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DiscontinuedOperationDetail1</Role>
      <ShortName>DISCONTINUED OPERATION (Detail 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DiscontinuedOperationTables</ParentRole>
      <Position>179</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R180.htm</HtmlFileName>
      <LongName>1180 - Disclosure - DISCONTINUED OPERATION (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DiscontinuedOperationDetailsTextual</Role>
      <ShortName>DISCONTINUED OPERATION (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DiscontinuedOperationTables</ParentRole>
      <Position>180</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R181.htm</HtmlFileName>
      <LongName>1181 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleDetails</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleTables</ParentRole>
      <Position>181</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R182.htm</HtmlFileName>
      <LongName>1182 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleDetails1</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleTables</ParentRole>
      <Position>182</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R183.htm</HtmlFileName>
      <LongName>1183 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE (Detail 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleDetail2</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE (Detail 2)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleTables</ParentRole>
      <Position>183</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R184.htm</HtmlFileName>
      <LongName>1184 - Disclosure - ASSETS CLASSIFIED AS HELD FOR SALE (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleDetailsTextual</Role>
      <ShortName>ASSETS CLASSIFIED AS HELD FOR SALE (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AssetsClassifiedAsHeldForSaleTables</ParentRole>
      <Position>184</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R185.htm</HtmlFileName>
      <LongName>1185 - Disclosure - ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinessesDetails1</Role>
      <ShortName>ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinessesTables</ParentRole>
      <Position>185</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R186.htm</HtmlFileName>
      <LongName>1186 - Disclosure - ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinessesDetailsTextual</Role>
      <ShortName>ACQUISITION OF ASSETS AND DISPOSAL OF BUSINESSES (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/AcquisitionOfAssetsAndDisposalOfBusinessesTables</ParentRole>
      <Position>186</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R187.htm</HtmlFileName>
      <LongName>1187 - Disclosure - EARNINGS PER SHARE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShareDetails</Role>
      <ShortName>EARNINGS PER SHARE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EarningsPerShareTables</ParentRole>
      <Position>187</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R188.htm</HtmlFileName>
      <LongName>1188 - Disclosure - EARNINGS PER SHARE (Details 1)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShareDetails1</Role>
      <ShortName>EARNINGS PER SHARE (Details 1)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EarningsPerShareTables</ParentRole>
      <Position>188</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R189.htm</HtmlFileName>
      <LongName>1189 - Disclosure - EARNINGS PER SHARE (Details 3)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShareDetails3</Role>
      <ShortName>EARNINGS PER SHARE (Details 3)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EarningsPerShareTables</ParentRole>
      <Position>189</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R190.htm</HtmlFileName>
      <LongName>1190 - Disclosure - EARNINGS PER SHARE (Details 4)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EarningsPerShareDetails4</Role>
      <ShortName>EARNINGS PER SHARE (Details 4)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EarningsPerShareTables</ParentRole>
      <Position>190</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R191.htm</HtmlFileName>
      <LongName>1191 - Disclosure - DIVIDENDS (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/DividendsDetailsTextual</Role>
      <ShortName>DIVIDENDS (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/DividendsTables</ParentRole>
      <Position>191</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R192.htm</HtmlFileName>
      <LongName>1192 - Disclosure - NON-CONTROLLING INTEREST (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/NonControllingInterestDetail</Role>
      <ShortName>NON-CONTROLLING INTEREST (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/NonControllingInterestTables</ParentRole>
      <Position>192</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R193.htm</HtmlFileName>
      <LongName>1193 - Disclosure - COMMITMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/CommitmentsDetails</Role>
      <ShortName>COMMITMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/CommitmentsTables</ParentRole>
      <Position>193</Position>
    </Report>
    <Report instance="grin-20211231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R194.htm</HtmlFileName>
      <LongName>1194 - Disclosure - EVENTS AFTER THE REPORTING PERIOD (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.grinshipping.com/role/EventsAfterTheReportingPeriodDetailsTextual</Role>
      <ShortName>EVENTS AFTER THE REPORTING PERIOD (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.grinshipping.com/role/EventsAfterTheReportingPeriod</ParentRole>
      <Position>194</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="20-F" original="grin-20211231.htm">grin-20211231.htm</File>
    <File>grin-20211231.xsd</File>
    <File>grin-20211231_cal.xml</File>
    <File>grin-20211231_def.xml</File>
    <File>grin-20211231_lab.xml</File>
    <File>grin-20211231_pre.xml</File>
    <File>gsh084_ex12-1.htm</File>
    <File>gsh084_ex12-2.htm</File>
    <File>gsh084_ex13-1.htm</File>
    <File>gsh084_ex13-2.htm</File>
    <File>gsh084_ex15-2.htm</File>
    <File>gsh084_ex4-20h.htm</File>
    <File>gsh084_ex4-25d.htm</File>
    <File>gsh084_ex4-26a.htm</File>
    <File>gsh084_ex4-26b.htm</File>
    <File>gsh084_ex4-31.htm</File>
    <File>gsh084_ex8-1b.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="2300">http://xbrl.ifrs.org/taxonomy/2021-03-24/ifrs-full</BaseTaxonomy>
    <BaseTaxonomy items="45">http://xbrl.sec.gov/dei/2021q4</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
