<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>208</ContextCount>
  <ElementCount>270</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>52</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Condensed Consolidated Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Condensed Consolidated Statements of Operations (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperationsUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Operations (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedStatementsOfComprehensiveLossIncomeUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Condensed Consolidated Statements of Stockholders' Deficit (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedStatementsOfStockholdersDeficitUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Stockholders' Deficit (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/StatementCondensedConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Description of the Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDescriptionOfBusiness</Role>
      <ShortName>Description of the Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureBasisOfPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Restricted Cash</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRestrictedCash</Role>
      <ShortName>Restricted Cash</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAcquisitions1</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Product Warranties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureProductWarranties</Role>
      <ShortName>Product Warranties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Debt Financing and Credit Facilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilities</Role>
      <ShortName>Debt Financing and Credit Facilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Warrants</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureWarrants</Role>
      <ShortName>Warrants</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureStockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Derivatives</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivatives</Role>
      <ShortName>Derivatives</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995635 - Disclosure - (Loss) Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShare</Role>
      <ShortName>(Loss) Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Related Parties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRelatedParties</Role>
      <ShortName>Related Parties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Basis of Presentation (Policy)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureBasisOfPresentationPolicy</Role>
      <ShortName>Basis of Presentation (Policy)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Revenue Recognition (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognitionTables</Role>
      <ShortName>Revenue Recognition (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognition</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformation</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurements</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Restricted Cash (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRestrictedCashTables</Role>
      <ShortName>Restricted Cash (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRestrictedCash</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventories</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Product Warranties (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureProductWarrantiesTables</Role>
      <ShortName>Product Warranties (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureProductWarranties</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Debt Financing and Credit Facilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilitiesTables</Role>
      <ShortName>Debt Financing and Credit Facilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilities</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncome</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Employee Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlansTables</Role>
      <ShortName>Employee Benefit Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlans</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Derivatives (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesTables</Role>
      <ShortName>Derivatives (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivatives</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995815 - Disclosure - (Loss) Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShareTables</Role>
      <ShortName>(Loss) Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShare</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Revenue Recognition (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognitionNarrativeDetails</Role>
      <ShortName>Revenue Recognition (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognitionTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Revenue Recognition (Schedule of Revenue Recognition) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognitionScheduleOfRevenueRecognitionDetails</Role>
      <ShortName>Revenue Recognition (Schedule of Revenue Recognition) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRevenueRecognitionTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Segment Information (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationNarrativeDetails</Role>
      <ShortName>Segment Information (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Segment Information (Schedule of Segment Reporting Information, by Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationScheduleOfSegmentReportingInformationBySegmentDetails</Role>
      <ShortName>Segment Information (Schedule of Segment Reporting Information, by Segment) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Segment Information (Reconciliation of Assets from Segment to Consolidated) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationReconciliationOfAssetsFromSegmentToConsolidatedDetails</Role>
      <ShortName>Segment Information (Reconciliation of Assets from Segment to Consolidated) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Segment Information (Geographic Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationGeographicInformationDetails</Role>
      <ShortName>Segment Information (Geographic Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureSegmentInformationTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Fair Value Measurements (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Fair Value Measurements (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurementsTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Fair Value Measurements (Fair Value, Assets Measured on Recurring Basis and Non-Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurementsFairValueAssetsMeasuredOnRecurringBasisAndNonRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements (Fair Value, Assets Measured on Recurring Basis and Non-Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureFairValueMeasurementsTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRestrictedCashDetails</Role>
      <ShortName>Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRestrictedCashTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Inventories (Schedule of Inventory Current) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventoriesScheduleOfInventoryCurrentDetails</Role>
      <ShortName>Inventories (Schedule of Inventory Current) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventoriesTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Inventories (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventoriesNarrativeDetails</Role>
      <ShortName>Inventories (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureInventoriesTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Acquisitions - Purchase Price Allocation Resulting In The Bargain Purchase Gain (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAcquisitionsPurchasePriceAllocationResultingInTheBargainPurchaseGainDetails</Role>
      <ShortName>Acquisitions - Purchase Price Allocation Resulting In The Bargain Purchase Gain (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Acquisitions (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAcquisitionsAdditionalInformationDetails</Role>
      <ShortName>Acquisitions (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAcquisitions1</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Product Warranties - Changes in Warranty Reserve (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureProductWarrantiesChangesInWarrantyReserveDetails</Role>
      <ShortName>Product Warranties - Changes in Warranty Reserve (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Debt Financing and Credit Facilities (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilitiesNarrativeDetails</Role>
      <ShortName>Debt Financing and Credit Facilities (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilitiesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>996015 - Disclosure - Debt Financing and Credit Facilities (Long-Term Debt) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilitiesLongtermDebtDetails</Role>
      <ShortName>Debt Financing and Credit Facilities (Long-Term Debt) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDebtFinancingAndCreditFacilitiesTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>996035 - Disclosure - Warrants (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureWarrantsAdditionalInformationDetails</Role>
      <ShortName>Warrants (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureWarrants</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Accumulated Other Comprehensive Income (Schedule of Changes in Accumulated Other Comprehensive Income (Loss)) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeScheduleOfChangesInAccumulatedOtherComprehensiveIncomeLossDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Schedule of Changes in Accumulated Other Comprehensive Income (Loss)) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>996065 - Disclosure - Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeComponentsOfAccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>996075 - Disclosure - Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeComponentsOfAccumulatedOtherComprehensiveIncomeParentheticalDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>996085 - Disclosure - Stock-Based Compensation (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureStockBasedCompensationNarrativeDetails</Role>
      <ShortName>Stock-Based Compensation (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureStockBasedCompensation</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>996105 - Disclosure - Employee Benefit Plans (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlansNarrativeDetails</Role>
      <ShortName>Employee Benefit Plans (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlansTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>996115 - Disclosure - Employee Benefit Plans (Components of Net Periodic Benefit Cost) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlansComponentsOfNetPeriodicBenefitCostDetails</Role>
      <ShortName>Employee Benefit Plans (Components of Net Periodic Benefit Cost) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureEmployeeBenefitPlansTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>996125 - Disclosure - Derivatives (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesAdditionalInformationDetails</Role>
      <ShortName>Derivatives (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>996135 - Disclosure - Derivatives - Schedule of Notional Amounts of Outstanding Foreign Currency Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesScheduleOfNotionalAmountsOfOutstandingForeignCurrencyDerivativesDetails</Role>
      <ShortName>Derivatives - Schedule of Notional Amounts of Outstanding Foreign Currency Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>996145 - Disclosure - Derivatives - Schedule of Fair Value of Outstanding Foreign Currency Derivatives Designated as Hedges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesScheduleOfFairValueOfOutstandingForeignCurrencyDerivativesDesignatedAsHedgesDetails</Role>
      <ShortName>Derivatives - Schedule of Fair Value of Outstanding Foreign Currency Derivatives Designated as Hedges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>996155 - Disclosure - Derivatives - Schedule of Pre-tax Realized Gain on Foreign Currency Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureDerivativesScheduleOfPretaxRealizedGainOnForeignCurrencyDerivativesDetails</Role>
      <ShortName>Derivatives - Schedule of Pre-tax Realized Gain on Foreign Currency Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>996175 - Disclosure - (Loss) Earnings Per Share - Schedule of (Weighted Average Common Shares Outstanding) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShareScheduleOfWeightedAverageCommonSharesOutstandingDetails</Role>
      <ShortName>(Loss) Earnings Per Share - Schedule of (Weighted Average Common Shares Outstanding) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>996185 - Disclosure - (Loss) Earnings Per Share (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShareNarrativeDetails</Role>
      <ShortName>(Loss) Earnings Per Share (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureLossEarningsPerShareTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>996205 - Disclosure - Related Parties (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRelatedPartiesNarrativeDetails</Role>
      <ShortName>Related Parties (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureRelatedParties</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="rail-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>996215 - Disclosure - Income Taxes (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails</Role>
      <ShortName>Income Taxes (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.freightcaramerica.com/20260630/taxonomy/role/DisclosureIncomeTaxes</ParentRole>
      <Position>70</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="rail-20260630.htm">rail-20260630.htm</File>
    <File>rail-20260630.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="5">http://fasb.org/srt/2026</BaseTaxonomy>
    <BaseTaxonomy items="772">http://fasb.org/us-gaap/2026</BaseTaxonomy>
    <BaseTaxonomy items="33">http://xbrl.sec.gov/dei/2026</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2026</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
