<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>782</ContextCount>
  <ElementCount>711</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>318</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>19</UnitCount>
  <MyReports>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000100 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>010000 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>010100 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>020000 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>020100 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>030000 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND MEZZANINE EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedStatementsOfShareholdersEquityAndMezzanineEquity</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND MEZZANINE EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>040000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>060100 - Disclosure - Basis of Presentation and General information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformation</Role>
      <ShortName>Basis of Presentation and General information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>060200 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncements</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>060300 - Disclosure - Discontinued operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DiscontinuedOperations</Role>
      <ShortName>Discontinued operations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>060400 - Disclosure - Transactions with Related Parties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedParties</Role>
      <ShortName>Transactions with Related Parties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>060500 - Disclosure - Deferred Charges, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DeferredChargesNet</Role>
      <ShortName>Deferred Charges, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>060600 - Disclosure - Fair Value of Acquired Time Charters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FairValueOfAcquiredTimeCharters</Role>
      <ShortName>Fair Value of Acquired Time Charters</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>060700 - Disclosure - Vessels, net/Assets held for sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSale</Role>
      <ShortName>Vessels, net/Assets held for sale</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>060800 - Disclosure - Acquisition of MPC Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/AcquisitionOfMpcCapital</Role>
      <ShortName>Acquisition of MPC Capital</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>060900 - Disclosure - Property and Equipment, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/PropertyAndEquipmentNet</Role>
      <ShortName>Property and Equipment, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>061000 - Disclosure - Intangible Assets, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IntangibleAssetsNet</Role>
      <ShortName>Intangible Assets, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>061100 - Disclosure - Equity method investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityMethodInvestments</Role>
      <ShortName>Equity method investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>061200 - Disclosure - Long-Term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt</Role>
      <ShortName>Long-Term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>061300 - Disclosure - Investment in equity securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InvestmentInEquitySecurities</Role>
      <ShortName>Investment in equity securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>061400 - Disclosure - Equity Capital Structure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructure</Role>
      <ShortName>Equity Capital Structure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>061500 - Disclosure - Financial Instruments and Fair Value Disclosures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FinancialInstrumentsAndFairValueDisclosures</Role>
      <ShortName>Financial Instruments and Fair Value Disclosures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>061600 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>061700 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>061800 - Disclosure - Earnings Per Common Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EarningsPerCommonShare</Role>
      <ShortName>Earnings Per Common Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>061900 - Disclosure - Revenues</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/Revenues</Role>
      <ShortName>Revenues</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>062000 - Disclosure - Vessel Operating Expenses and Voyage Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselOperatingExpensesAndVoyageExpenses</Role>
      <ShortName>Vessel Operating Expenses and Voyage Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>062100 - Disclosure - General and Administrative Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/GeneralAndAdministrativeExpenses</Role>
      <ShortName>General and Administrative Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>062200 - Disclosure - Interest and Finance Costs</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InterestAndFinanceCosts</Role>
      <ShortName>Interest and Finance Costs</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>062300 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>062400 - Disclosure - Share-based compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SharebasedCompensation</Role>
      <ShortName>Share-based compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>062500 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>062600 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>062700 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InsiderTradingPoliciesAndProcedures</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>062800 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>070200 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsPolicies</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncements</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>080100 - Disclosure - Basis of Presentation and General Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationTables</Role>
      <ShortName>Basis of Presentation and General Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>080200 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsTables</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncements</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>080300 - Disclosure - Discontinued operations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DiscontinuedOperationsTables</Role>
      <ShortName>Discontinued operations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/DiscontinuedOperations</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>080400 - Disclosure - Transactions with Related Parties (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesTables</Role>
      <ShortName>Transactions with Related Parties (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/TransactionsWithRelatedParties</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>080500 - Disclosure - Deferred Charges, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DeferredChargesNetTables</Role>
      <ShortName>Deferred Charges, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/DeferredChargesNet</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>080700 - Disclosure - Vessels, net/Assets held for sale (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSaleTables</Role>
      <ShortName>Vessels, net/Assets held for sale (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/VesselsNetAssetsHeldForSale</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>080800 - Disclosure - Acquisition of MPC Capital (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/AcquisitionOfMpcCapitalTables</Role>
      <ShortName>Acquisition of MPC Capital (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/AcquisitionOfMpcCapital</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>080900 - Disclosure - Property and Equipment, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/PropertyAndEquipmentNetTables</Role>
      <ShortName>Property and Equipment, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/PropertyAndEquipmentNet</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>081000 - Disclosure - Intangible Assets, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IntangibleAssetsNetTables</Role>
      <ShortName>Intangible Assets, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/IntangibleAssetsNet</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>081100 - Disclosure - Equity method investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityMethodInvestmentsTables</Role>
      <ShortName>Equity method investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/EquityMethodInvestments</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>081200 - Disclosure - Long-Term Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebtTables</Role>
      <ShortName>Long-Term Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/LongtermDebt</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>081300 - Disclosure - Investment in equity securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InvestmentInEquitySecuritiesTables</Role>
      <ShortName>Investment in equity securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/InvestmentInEquitySecurities</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>081500 - Disclosure - Financial Instruments and Fair Value Disclosures (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FinancialInstrumentsAndFairValueDisclosuresTables</Role>
      <ShortName>Financial Instruments and Fair Value Disclosures (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/FinancialInstrumentsAndFairValueDisclosures</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>081600 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/Leases</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>081700 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>081800 - Disclosure - Earnings Per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EarningsPerCommonShareTables</Role>
      <ShortName>Earnings Per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/EarningsPerCommonShare</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>081900 - Disclosure - Revenues (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/RevenuesTables</Role>
      <ShortName>Revenues (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/Revenues</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>082000 - Disclosure - Vessel Operating Expenses and Voyage Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselOperatingExpensesAndVoyageExpensesTables</Role>
      <ShortName>Vessel Operating Expenses and Voyage Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/VesselOperatingExpensesAndVoyageExpenses</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>082100 - Disclosure - General and Administrative Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/GeneralAndAdministrativeExpensesTables</Role>
      <ShortName>General and Administrative Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/GeneralAndAdministrativeExpenses</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>082200 - Disclosure - Interest and Finance Costs (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InterestAndFinanceCostsTables</Role>
      <ShortName>Interest and Finance Costs (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/InterestAndFinanceCosts</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>082300 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/IncomeTaxes</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>082400 - Disclosure - Share-based compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SharebasedCompensationTables</Role>
      <ShortName>Share-based compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SharebasedCompensation</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>082500 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SegmentInformation</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>090100 - Disclosure - Basis of Presentation and General information, General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationGeneralInformationDetails</Role>
      <ShortName>Basis of Presentation and General information, General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>090102 - Disclosure - Basis of Presentation and General information, Assets and Liabilities of Toro (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationAssetsAndLiabilitiesOfToroDetails</Role>
      <ShortName>Basis of Presentation and General information, Assets and Liabilities of Toro (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>090104 - Disclosure - Basis of Presentation and General information, Consolidated Subsidiaries (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationConsolidatedSubsidiariesDetails</Role>
      <ShortName>Basis of Presentation and General information, Consolidated Subsidiaries (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>090106 - Disclosure - Basis of Presentation and General information, Consolidated Majority-Owned Subsidiaries (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationConsolidatedMajorityownedSubsidiariesDetails</Role>
      <ShortName>Basis of Presentation and General information, Consolidated Majority-Owned Subsidiaries (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>090108 - Disclosure - Basis of Presentation and General information, Revenue from Charters (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/BasisOfPresentationAndGeneralInformationRevenueFromChartersDetails</Role>
      <ShortName>Basis of Presentation and General information, Revenue from Charters (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>090200 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Segment Reporting (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsSegmentReportingDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Segment Reporting (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>090202 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Foreign Currency Translation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsForeignCurrencyTranslationDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Foreign Currency Translation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>090204 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Accounts Receivable Trade, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsAccountsReceivableTradeNetDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Accounts Receivable Trade, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>090206 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsIntangibleAssetsDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>090208 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Insurance Claims (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsInsuranceClaimsDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Insurance Claims (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>090210 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Vessels' Depreciation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsVesselsDepreciationDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Vessels' Depreciation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>090212 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Impairment of Vessels (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsImpairmentOfVesselsDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Impairment of Vessels (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>090214 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsPropertyPlantAndEquipmentDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>090216 - Disclosure - Significant Accounting Policies and Recent Accounting Pronouncements, Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsLeasesDetails</Role>
      <ShortName>Significant Accounting Policies and Recent Accounting Pronouncements, Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SignificantAccountingPoliciesAndRecentAccountingPronouncementsTables</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>090300 - Disclosure - Discontinued operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DiscontinuedOperationsDetails</Role>
      <ShortName>Discontinued operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/DiscontinuedOperationsTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>090400 - Disclosure - Transactions with Related Parties, Summary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesSummaryDetails</Role>
      <ShortName>Transactions with Related Parties, Summary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>090402 - Disclosure - Transactions with Related Parties, Castor Ships (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesCastorShipsDetails</Role>
      <ShortName>Transactions with Related Parties, Castor Ships (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>090404 - Disclosure - Transactions with Related Parties, Pavimar (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesPavimarDetails</Role>
      <ShortName>Transactions with Related Parties, Pavimar (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>090406 - Disclosure - Transactions with Related Parties, Investment in Related Party (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesInvestmentInRelatedPartyDetails</Role>
      <ShortName>Transactions with Related Parties, Investment in Related Party (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>090408 - Disclosure - Transactions with Related Parties, Issuance of Series D Preferred shares to Toro (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesIssuanceOfSeriesDPreferredSharesToToroDetails</Role>
      <ShortName>Transactions with Related Parties, Issuance of Series D Preferred shares to Toro (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>090410 - Disclosure - Transactions with Related Parties, Long-Term Debt, Related Party (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesLongtermDebtRelatedPartyDetails</Role>
      <ShortName>Transactions with Related Parties, Long-Term Debt, Related Party (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>090414 - Disclosure - Transactions with Related Parties, Vessel Acquisitions/Disposals (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesVesselAcquisitionsDisposalsDetails</Role>
      <ShortName>Transactions with Related Parties, Vessel Acquisitions/Disposals (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>090416 - Disclosure - Transactions with Related Parties, MPC Capital Related Parties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/TransactionsWithRelatedPartiesMpcCapitalRelatedPartiesDetails</Role>
      <ShortName>Transactions with Related Parties, MPC Capital Related Parties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>090500 - Disclosure - Deferred Charges, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/DeferredChargesNetDetails</Role>
      <ShortName>Deferred Charges, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/DeferredChargesNetTables</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>090600 - Disclosure - Fair Value of Acquired Time Charters (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FairValueOfAcquiredTimeChartersDetails</Role>
      <ShortName>Fair Value of Acquired Time Charters (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/FairValueOfAcquiredTimeCharters</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>090700 - Disclosure - Vessels, net/Assets held for sale, Net Book Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSaleNetBookValueDetails</Role>
      <ShortName>Vessels, net/Assets held for sale, Net Book Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>090702 - Disclosure - Vessels, net/Assets held for sale, Vessel Acquisitions and Other Capital Expenditures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSaleVesselAcquisitionsAndOtherCapitalExpendituresDetails</Role>
      <ShortName>Vessels, net/Assets held for sale, Vessel Acquisitions and Other Capital Expenditures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>090704 - Disclosure - Vessels, net/Assets held for sale, Disposal of Vessels (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSaleDisposalOfVesselsDetails</Role>
      <ShortName>Vessels, net/Assets held for sale, Disposal of Vessels (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>090706 - Disclosure - Vessels, net/Assets held for sale, Assets Held for Sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselsNetAssetsHeldForSaleAssetsHeldForSaleDetails</Role>
      <ShortName>Vessels, net/Assets held for sale, Assets Held for Sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>090802 - Disclosure - Acquisition of MPC Capital (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/AcquisitionOfMpcCapitalDetails</Role>
      <ShortName>Acquisition of MPC Capital (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/AcquisitionOfMpcCapitalTables</ParentRole>
      <Position>89</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>090900 - Disclosure - Property and Equipment, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/PropertyAndEquipmentNetDetails</Role>
      <ShortName>Property and Equipment, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/PropertyAndEquipmentNetTables</ParentRole>
      <Position>90</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>091000 - Disclosure - Intangible Assets, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IntangibleAssetsNetDetails</Role>
      <ShortName>Intangible Assets, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/IntangibleAssetsNetTables</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>091100 - Disclosure - Equity method investments, Ownership Interests and Carrying Amount (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityMethodInvestmentsOwnershipInterestsAndCarryingAmountDetails</Role>
      <ShortName>Equity method investments, Ownership Interests and Carrying Amount (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>091102 - Disclosure - Equity method investments, Summarized Consolidated Financial Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityMethodInvestmentsSummarizedConsolidatedFinancialInformationDetails</Role>
      <ShortName>Equity method investments, Summarized Consolidated Financial Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>091200 - Disclosure - Long-Term Debt, Summary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebtSummaryDetails</Role>
      <ShortName>Long-Term Debt, Summary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>091202 - Disclosure - Long-Term Debt, $11.0 Million Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt110MillionTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, $11.0 Million Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>091206 - Disclosure - Long-Term Debt, $15.29 Million Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt1529MillionTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, $15.29 Million Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>091208 - Disclosure - Long-Term Debt, $40.75 Million Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt4075MillionTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, $40.75 Million Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>091212 - Disclosure - Long-Term Debt, $55.0 Million Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt550MillionTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, $55.0 Million Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>091214 - Disclosure - Long-Term Debt, $22.5 Million Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt225MillionTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, $22.5 Million Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>091216 - Disclosure - Long-Term Debt, 5 Million Euro Term Loan Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebt5MillionEuroTermLoanFacilityDetails</Role>
      <ShortName>Long-Term Debt, 5 Million Euro Term Loan Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>091218 - Disclosure - Long-Term Debt, Annual Principal Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LongtermDebtAnnualPrincipalPaymentsDetails</Role>
      <ShortName>Long-Term Debt, Annual Principal Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>091300 - Disclosure - Investment in equity securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InvestmentInEquitySecuritiesDetails</Role>
      <ShortName>Investment in equity securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/InvestmentInEquitySecuritiesTables</ParentRole>
      <Position>102</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>091400 - Disclosure - Equity Capital Structure, Capital Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureCapitalStockDetails</Role>
      <ShortName>Equity Capital Structure, Capital Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>091402 - Disclosure - Equity Capital Structure, Reverse Stock Split (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureReverseStockSplitDetails</Role>
      <ShortName>Equity Capital Structure, Reverse Stock Split (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>091404 - Disclosure - Equity Capital Structure, Common Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureCommonSharesDetails</Role>
      <ShortName>Equity Capital Structure, Common Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>091406 - Disclosure - Equity Capital Structure, 2020 June Equity Offering (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructure2020JuneEquityOfferingDetails</Role>
      <ShortName>Equity Capital Structure, 2020 June Equity Offering (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>091408 - Disclosure - Equity Capital Structure, 2020 July Equity Offering (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructure2020JulyEquityOfferingDetails</Role>
      <ShortName>Equity Capital Structure, 2020 July Equity Offering (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>107</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>091410 - Disclosure - Equity Capital Structure, 2021 Third Registered Direct Equity Offering (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructure2021ThirdRegisteredDirectEquityOfferingDetails</Role>
      <ShortName>Equity Capital Structure, 2021 Third Registered Direct Equity Offering (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>108</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>091412 - Disclosure - Equity Capital Structure, Warrants Repurchase (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureWarrantsRepurchaseDetails</Role>
      <ShortName>Equity Capital Structure, Warrants Repurchase (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>109</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>091414 - Disclosure - Equity Capital Structure, May 2023 At-the-Market Common Shares Offering Program (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureMay2023AtthemarketCommonSharesOfferingProgramDetails</Role>
      <ShortName>Equity Capital Structure, May 2023 At-the-Market Common Shares Offering Program (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>110</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>091416 - Disclosure - Equity Capital Structure, Nasdaq Minimum Bid Price Requirement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureNasdaqMinimumBidPriceRequirementDetails</Role>
      <ShortName>Equity Capital Structure, Nasdaq Minimum Bid Price Requirement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>111</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>091418 - Disclosure - Equity Capital Structure, Description of Series B Preferred Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureDescriptionOfSeriesBPreferredSharesDetails</Role>
      <ShortName>Equity Capital Structure, Description of Series B Preferred Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>112</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>091420 - Disclosure - Equity Capital Structure, Series D Cumulative Perpetual Convertible Preferred Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EquityCapitalStructureSeriesDCumulativePerpetualConvertiblePreferredSharesDetails</Role>
      <ShortName>Equity Capital Structure, Series D Cumulative Perpetual Convertible Preferred Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>113</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>091500 - Disclosure - Financial Instruments and Fair Value Disclosures, Derivative Contracts Measured on Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FinancialInstrumentsAndFairValueDisclosuresDerivativeContractsMeasuredOnRecurringBasisDetails</Role>
      <ShortName>Financial Instruments and Fair Value Disclosures, Derivative Contracts Measured on Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>114</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>091502 - Disclosure - Financial Instruments and Fair Value Disclosures, Assets Measured at Fair Value on Non-recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/FinancialInstrumentsAndFairValueDisclosuresAssetsMeasuredAtFairValueOnNonrecurringBasisDetails</Role>
      <ShortName>Financial Instruments and Fair Value Disclosures, Assets Measured at Fair Value on Non-recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>115</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>091600 - Disclosure - Leases, Lease Cost (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LeasesLeaseCostDetails</Role>
      <ShortName>Leases, Lease Cost (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>116</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>091602 - Disclosure - Leases, Other Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LeasesOtherInformationDetails</Role>
      <ShortName>Leases, Other Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>117</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>091604 - Disclosure - Leases, Undiscounted Cash Flows of Lease Liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/LeasesUndiscountedCashFlowsOfLeaseLiabilityDetails</Role>
      <ShortName>Leases, Undiscounted Cash Flows of Lease Liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>118</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>091700 - Disclosure - Commitments and Contingencies, Commitments Under Long-Term Lease Contracts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/CommitmentsAndContingenciesCommitmentsUnderLongtermLeaseContractsDetails</Role>
      <ShortName>Commitments and Contingencies, Commitments Under Long-Term Lease Contracts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>119</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>091702 - Disclosure - Commitments and Contingencies, Claims and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/CommitmentsAndContingenciesClaimsAndContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies, Claims and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>120</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>091800 - Disclosure - Earnings Per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/EarningsPerCommonShareDetails</Role>
      <ShortName>Earnings Per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/EarningsPerCommonShareTables</ParentRole>
      <Position>121</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>091900 - Disclosure - Revenues, Vessel Revenues (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/RevenuesVesselRevenuesDetails</Role>
      <ShortName>Revenues, Vessel Revenues (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>122</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>091902 - Disclosure - Revenues, Revenue from Services (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/RevenuesRevenueFromServicesDetails</Role>
      <ShortName>Revenues, Revenue from Services (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>123</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>092000 - Disclosure - Vessel Operating Expenses and Voyage Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/VesselOperatingExpensesAndVoyageExpensesDetails</Role>
      <ShortName>Vessel Operating Expenses and Voyage Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/VesselOperatingExpensesAndVoyageExpensesTables</ParentRole>
      <Position>124</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>092100 - Disclosure - General and Administrative Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/GeneralAndAdministrativeExpensesDetails</Role>
      <ShortName>General and Administrative Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/GeneralAndAdministrativeExpensesTables</ParentRole>
      <Position>125</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>092200 - Disclosure - Interest and Finance Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/InterestAndFinanceCostsDetails</Role>
      <ShortName>Interest and Finance Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/InterestAndFinanceCostsTables</ParentRole>
      <Position>126</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>092300 - Disclosure - Income Taxes, Summary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesSummaryDetails</Role>
      <ShortName>Income Taxes, Summary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>127</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>092304 - Disclosure - Income Taxes, Provision for Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesProvisionForIncomeTaxesDetails</Role>
      <ShortName>Income Taxes, Provision for Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>128</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>092306 - Disclosure - Income Taxes, Effective Income Tax Rate Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesEffectiveIncomeTaxRateReconciliationDetails</Role>
      <ShortName>Income Taxes, Effective Income Tax Rate Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>129</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>092308 - Disclosure - Income Taxes, Components of Deferred Tax Account Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesComponentsOfDeferredTaxAccountBalancesDetails</Role>
      <ShortName>Income Taxes, Components of Deferred Tax Account Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>130</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>092310 - Disclosure - Income Taxes, Uncertain Tax Positions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/IncomeTaxesUncertainTaxPositionsDetails</Role>
      <ShortName>Income Taxes, Uncertain Tax Positions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>131</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>092400 - Disclosure - Share-based compensation, Assumptions for Options Granted (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SharebasedCompensationAssumptionsForOptionsGrantedDetails</Role>
      <ShortName>Share-based compensation, Assumptions for Options Granted (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>132</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>092402 - Disclosure - Share-based compensation, Options Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SharebasedCompensationOptionsActivityDetails</Role>
      <ShortName>Share-based compensation, Options Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>133</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>092500 - Disclosure - Segment Information, Information about Company's Reportable Segments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SegmentInformationInformationAboutCompanySReportableSegmentsDetails</Role>
      <ShortName>Segment Information, Information about Company's Reportable Segments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>134</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>092502 - Disclosure - Segment Information, Reconciliation of Total Segment Assets to Total Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SegmentInformationReconciliationOfTotalSegmentAssetsToTotalAssetsDetails</Role>
      <ShortName>Segment Information, Reconciliation of Total Segment Assets to Total Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>135</Position>
    </Report>
    <Report instance="ef20038931_20f.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>092600 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://castormaritime.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://castormaritime.com/role/SubsequentEvents</ParentRole>
      <Position>136</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>ctrm-20241231.xsd</File>
    <File>ctrm-20241231_cal.xml</File>
    <File>ctrm-20241231_def.xml</File>
    <File>ctrm-20241231_lab.xml</File>
    <File>ctrm-20241231_pre.xml</File>
    <File doctype="20-F" isDefinitelyFs="true" isUsgaap="true" original="ef20038931_20f.htm">ef20038931_20f.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2024</BaseTaxonomy>
    <BaseTaxonomy items="1712">http://fasb.org/us-gaap/2024</BaseTaxonomy>
    <BaseTaxonomy items="16">http://xbrl.sec.gov/cyd/2024</BaseTaxonomy>
    <BaseTaxonomy items="188">http://xbrl.sec.gov/dei/2024</BaseTaxonomy>
    <BaseTaxonomy items="1">http://xbrl.sec.gov/ecd/2024</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
