<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.8.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>613</ContextCount>
  <ElementCount>487</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>289</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>12</UnitCount>
  <MyReports>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00205 - Statement - Consolidated Statements of Operations (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfOperationsParenthetical</Role>
      <ShortName>Consolidated Statements of Operations (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00300 - Statement - Consolidated Statements of Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfComprehensiveLoss</Role>
      <ShortName>Consolidated Statements of Comprehensive Loss</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00400 - Statement - Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfEquity</Role>
      <ShortName>Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00405 - Statement - Consolidated Statements of Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfEquityParenthetical</Role>
      <ShortName>Consolidated Statements of Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>00500 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>00505 - Statement - Consolidated Statements of Cash Flows (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/StatementConsolidatedStatementsOfCashFlowsParenthetical</Role>
      <ShortName>Consolidated Statements of Cash Flows (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10101 - Disclosure - GENERAL INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureGeneralInformation</Role>
      <ShortName>GENERAL INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10201 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10301 - Disclosure - CASH FLOW INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCashFlowInformation</Role>
      <ShortName>CASH FLOW INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10401 - Disclosure - VESSEL ACQUISITIONS AND DISPOSITIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureVesselAcquisitionsAndDispositions</Role>
      <ShortName>VESSEL ACQUISITIONS AND DISPOSITIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10501 - Disclosure - INVESTMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureInvestments</Role>
      <ShortName>INVESTMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10601 - Disclosure - NET LOSS PER SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureNetLossPerShare</Role>
      <ShortName>NET LOSS PER SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10701 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureRelatedPartyTransactions</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>10801 - Disclosure - DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt</Role>
      <ShortName>DEBT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>10901 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11001 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFairValueOfFinancialInstruments</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>11101 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosurePrepaidExpensesAndOtherCurrentAndNoncurrentAssets</Role>
      <ShortName>PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>11201 - Disclosure - FIXED ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFixedAssets</Role>
      <ShortName>FIXED ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>11301 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED EXPENSES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccountsPayableAndAccruedExpenses</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED EXPENSES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>11401 - Disclosure - VOYAGE REVENUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureVoyageRevenue</Role>
      <ShortName>VOYAGE REVENUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>11501 - Disclosure - REORGANIZATION ITEMS, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureReorganizationItemsNet</Role>
      <ShortName>REORGANIZATION ITEMS, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>11601 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>11701 - Disclosure - SAVINGS PLAN</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSavingsPlan</Role>
      <ShortName>SAVINGS PLAN</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>11801 - Disclosure - STOCK-BASED COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensation</Role>
      <ShortName>STOCK-BASED COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>11901 - Disclosure - LEGAL PROCEEDINGS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureLegalProceedings</Role>
      <ShortName>LEGAL PROCEEDINGS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>12001 - Disclosure - UNAUDITED QUARTERLY RESULTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureUnauditedQuarterlyResultsOfOperations</Role>
      <ShortName>UNAUDITED QUARTERLY RESULTS OF OPERATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>12101 - Disclosure - SUBSEQUENT EVENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSubsequentEvents</Role>
      <ShortName>SUBSEQUENT EVENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>20202 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>30103 - Disclosure - GENERAL INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureGeneralInformationTables</Role>
      <ShortName>GENERAL INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureGeneralInformation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>30203 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>30603 - Disclosure - NET LOSS PER SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureNetLossPerShareTables</Role>
      <ShortName>NET LOSS PER SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureNetLossPerShare</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>30803 - Disclosure - DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtTables</Role>
      <ShortName>DEBT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureDebt</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>30903 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>31003 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFairValueOfFinancialInstrumentsTables</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureFairValueOfFinancialInstruments</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>31103 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosurePrepaidExpensesAndOtherCurrentAndNoncurrentAssetsTables</Role>
      <ShortName>PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosurePrepaidExpensesAndOtherCurrentAndNoncurrentAssets</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>31203 - Disclosure - FIXED ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFixedAssetsTables</Role>
      <ShortName>FIXED ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureFixedAssets</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>31303 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED EXPENSES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccountsPayableAndAccruedExpensesTables</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED EXPENSES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureAccountsPayableAndAccruedExpenses</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>31503 - Disclosure - REORGANIZATION ITEMS, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureReorganizationItemsNetTables</Role>
      <ShortName>REORGANIZATION ITEMS, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureReorganizationItemsNet</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>31803 - Disclosure - STOCK-BASED COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensationTables</Role>
      <ShortName>STOCK-BASED COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureStockBasedCompensation</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>32003 - Disclosure - UNAUDITED QUARTERLY RESULTS OF OPERATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureUnauditedQuarterlyResultsOfOperationsTables</Role>
      <ShortName>UNAUDITED QUARTERLY RESULTS OF OPERATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureUnauditedQuarterlyResultsOfOperations</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40101 - Disclosure - GENERAL INFORMATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureGeneralInformationDetails</Role>
      <ShortName>GENERAL INFORMATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureGeneralInformationTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40102 - Disclosure - GENERAL INFORMATION - Vessel Details (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureGeneralInformationVesselDetailsDetails</Role>
      <ShortName>GENERAL INFORMATION - Vessel Details (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>40103 - Disclosure - GENERAL INFORMATION - Other (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureGeneralInformationOtherDetails</Role>
      <ShortName>GENERAL INFORMATION - Other (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>40201 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Segment and Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesSegmentAndIncomeDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Segment and Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>40203 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesAssetsDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>40204 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment of assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesImpairmentOfAssetsDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment of assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>40205 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disposal of Vessels (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDisposalOfVesselsDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disposal of Vessels (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>40206 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesRestrictedCashDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>40207 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesInvestmentsDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>40208 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTaxesDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>40209 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration Risk (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesConcentrationRiskDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration Risk (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>40210 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recent Accounting Pronouncements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSummaryOfSignificantAccountingPoliciesRecentAccountingPronouncementsDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recent Accounting Pronouncements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>40301 - Disclosure - CASH FLOW INFORMATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCashFlowInformationDetails</Role>
      <ShortName>CASH FLOW INFORMATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureCashFlowInformation</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>40302 - Disclosure - CASH FLOW INFORMATION - Stock-Based Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCashFlowInformationStockBasedCompensationDetails</Role>
      <ShortName>CASH FLOW INFORMATION - Stock-Based Compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>40401 - Disclosure - VESSEL ACQUISITIONS AND DISPOSITIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureVesselAcquisitionsAndDispositionsDetails</Role>
      <ShortName>VESSEL ACQUISITIONS AND DISPOSITIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureVesselAcquisitionsAndDispositions</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>40501 - Disclosure - INVESTMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureInvestmentsDetails</Role>
      <ShortName>INVESTMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureInvestments</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>40601 - Disclosure - NET LOSS PER SHARE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureNetLossPerShareDetails</Role>
      <ShortName>NET LOSS PER SHARE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureNetLossPerShareTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>40701 - Disclosure - RELATED PARTY TRANSACTIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureRelatedPartyTransactionsDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureRelatedPartyTransactions</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>40801 - Disclosure - DEBT - Components of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtComponentsOfLongTermDebtDetails</Role>
      <ShortName>DEBT - Components of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>40802 - Disclosure - DEBT - Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtExpensesDetails</Role>
      <ShortName>DEBT - Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>40803 - Disclosure - DEBT - Commitment Letter (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtCommitmentLetterDetails</Role>
      <ShortName>DEBT - Commitment Letter (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>40804 - Disclosure - DEBT - $400 Million Credit Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt400MillionCreditFacilityDetails</Role>
      <ShortName>DEBT - $400 Million Credit Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>40805 - Disclosure - DEBT - $98M Credit Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt98mCreditFacilityDetails</Role>
      <ShortName>DEBT - $98M Credit Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>40806 - Disclosure - DEBT - 2014 Term Loan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt2014TermLoanDetails</Role>
      <ShortName>DEBT - 2014 Term Loan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>40807 - Disclosure - DEBT - Amendment and Consent Agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtAmendmentAndConsentAgreementsDetails</Role>
      <ShortName>DEBT - Amendment and Consent Agreements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>40808 - Disclosure - DEBT - 2015 Revolving Credit Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt2015RevolvingCreditFacilityDetails</Role>
      <ShortName>DEBT - 2015 Revolving Credit Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>40809 - Disclosure - DEBT - $148M Revolving Credit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt148mRevolvingCreditDetails</Role>
      <ShortName>DEBT - $148M Revolving Credit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>40810 - Disclosure - DEBT - $44M Term Loan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt44mTermLoanDetails</Role>
      <ShortName>DEBT - $44M Term Loan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>40811 - Disclosure - DEBT - $22M Term Loan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt22mTermLoanDetails</Role>
      <ShortName>DEBT - $22M Term Loan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>40812 - Disclosure - DEBT - $253M and $100M Term Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt253mAnd100mTermLoansDetails</Role>
      <ShortName>DEBT - $253M and $100M Term Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>40813 - Disclosure - DEBT - 2010 Line of Credit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebt2010LineOfCreditDetails</Role>
      <ShortName>DEBT - 2010 Line of Credit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>40814 - Disclosure - DEBT - Interest Rates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureDebtInterestRatesDetails</Role>
      <ShortName>DEBT - Interest Rates (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>40901 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossDetails</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>40902 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)- Reclassifications (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossReclassificationsDetails</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)- Reclassifications (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>41001 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS - RECURRING (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFairValueOfFinancialInstrumentsRecurringDetails</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS - RECURRING (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>41002 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS - NONRECURRING (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFairValueOfFinancialInstrumentsNonrecurringDetails</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS - NONRECURRING (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>41101 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosurePrepaidExpensesAndOtherCurrentAndNoncurrentAssetsDetails</Role>
      <ShortName>PREPAID EXPENSES AND OTHER CURRENT AND NONCURRENT ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosurePrepaidExpensesAndOtherCurrentAndNoncurrentAssetsTables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>41201 - Disclosure - FIXED ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureFixedAssetsDetails</Role>
      <ShortName>FIXED ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureFixedAssetsTables</ParentRole>
      <Position>82</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>41301 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED EXPENSES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureAccountsPayableAndAccruedExpensesDetails</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED EXPENSES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureAccountsPayableAndAccruedExpensesTables</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>41401 - Disclosure - VOYAGE REVENUE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureVoyageRevenueDetails</Role>
      <ShortName>VOYAGE REVENUE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureVoyageRevenue</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>41501 - Disclosure - REORGANIZATION ITEMS, NET (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureReorganizationItemsNetDetails</Role>
      <ShortName>REORGANIZATION ITEMS, NET (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureReorganizationItemsNetTables</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>41601 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCommitmentsAndContingenciesDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureCommitmentsAndContingencies</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>41602 - Disclosure - COMMITMENTS AND CONTINGENCIES - Settlements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureCommitmentsAndContingenciesSettlementsDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Settlements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>41701 - Disclosure - SAVINGS PLAN (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSavingsPlanDetails</Role>
      <ShortName>SAVINGS PLAN (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureSavingsPlan</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>41801 - Disclosure - STOCK-BASED COMPENSATION - Other (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensationOtherDetails</Role>
      <ShortName>STOCK-BASED COMPENSATION - Other (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>41802 - Disclosure - STOCK-BASED COMPENSATION - 2014 MIP (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensation2014MipDetails</Role>
      <ShortName>STOCK-BASED COMPENSATION - 2014 MIP (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>41803 - Disclosure - STOCK-BASED COMPENSATION - 2015 EIP Stock Options and Other (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensation2015EipStockOptionsAndOtherDetails</Role>
      <ShortName>STOCK-BASED COMPENSATION - 2015 EIP Stock Options and Other (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>41804 - Disclosure - STOCK-BASED COMPENSATION - 2015 EIP Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensation2015EipRestrictedStockUnitsDetails</Role>
      <ShortName>STOCK-BASED COMPENSATION - 2015 EIP Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>41805 - Disclosure - STOCK-BASED COMPENSATION - 2015 EIP Restricted Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureStockBasedCompensation2015EipRestrictedStockDetails</Role>
      <ShortName>STOCK-BASED COMPENSATION - 2015 EIP Restricted Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>41901 - Disclosure - LEGAL PROCEEDINGS - Claims and Complaints (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureLegalProceedingsClaimsAndComplaintsDetails</Role>
      <ShortName>LEGAL PROCEEDINGS - Claims and Complaints (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>42001 - Disclosure - UNAUDITED QUARTERLY RESULTS OF OPERATIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureUnauditedQuarterlyResultsOfOperationsDetails</Role>
      <ShortName>UNAUDITED QUARTERLY RESULTS OF OPERATIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureUnauditedQuarterlyResultsOfOperationsTables</ParentRole>
      <Position>95</Position>
    </Report>
    <Report instance="gnk-20171231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>42101 - Disclosure - SUBSEQUENT EVENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://gencoshipping.com/role/DisclosureSubsequentEventsDetails</Role>
      <ShortName>SUBSEQUENT EVENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://gencoshipping.com/role/DisclosureSubsequentEvents</ParentRole>
      <Position>96</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>gnk-20171231.xml</File>
    <File>gnk-20171231.xsd</File>
    <File>gnk-20171231_cal.xml</File>
    <File>gnk-20171231_def.xml</File>
    <File>gnk-20171231_lab.xml</File>
    <File>gnk-20171231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2014-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2016-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2016-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
