<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>671</ContextCount>
  <ElementCount>78</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>164</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>010000 - Disclosure - Form N-1A Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/N1aCover</Role>
      <ShortName>Form N-1A Cover</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>010002 - Disclosure - Investment Objectives and Goals</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/RiskReturn</Role>
      <ShortName>Investment Objectives and Goals</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>010003 - Disclosure - Fees and Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/FeesAndExpenses</Role>
      <ShortName>Fees and Expenses</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>010004 - Disclosure - Investment Strategy</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/InvestmentStrategy</Role>
      <ShortName>Investment Strategy</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>010005 - Disclosure - Investment Risks</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/InvestmentRisks</Role>
      <ShortName>Investment Risks</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>010006 - Disclosure - Performance Management</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/PerformanceManagement</Role>
      <ShortName>Performance Management</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>020010 - Disclosure - Shareholder Fees</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/ShareholderFeesData</Role>
      <ShortName>Shareholder Fees</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>020020 - Disclosure - Annual Fund Operating Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/OperatingExpensesData</Role>
      <ShortName>Annual Fund Operating Expenses</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>020030 - Disclosure - Expense Example</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/ExpenseExample</Role>
      <ShortName>Expense Example</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>020040 - Disclosure - Expense Example, No Redemption</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/ExpenseExampleNoRedemption</Role>
      <ShortName>Expense Example, No Redemption</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>020050 - Disclosure - Annual Total Returns</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/BarChartData</Role>
      <ShortName>Annual Total Returns</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>020060 - Disclosure - Average Annual Total Returns</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/PerformanceTableData</Role>
      <ShortName>Average Annual Total Returns</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>020100 - Document - Risk/Return Summary {Unlabeled} - First Eagle Global Fund - First Eagle Global Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleGlobalFundFirstEagleGlobalFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Global Fund - First Eagle Global Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>020101 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Global Fund - First Eagle Global Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleGlobalFundFirstEagleGlobalFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Global Fund - First Eagle Global Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>020102 - Document - Risk/Return Summary {Unlabeled} - First Eagle Overseas Fund - First Eagle Overseas Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleOverseasFundFirstEagleOverseasFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Overseas Fund - First Eagle Overseas Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>020103 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Overseas Fund - First Eagle Overseas Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleOverseasFundFirstEagleOverseasFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Overseas Fund - First Eagle Overseas Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>020104 - Document - Risk/Return Summary {Unlabeled} - First Eagle U.S. Fund - First Eagle U.S. Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleUSFundFirstEagleUSFund</Role>
      <ShortName>Risk/Return Summary- First Eagle U.S. Fund - First Eagle U.S. Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>020105 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle U.S. Fund - First Eagle U.S. Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleUSFundFirstEagleUSFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle U.S. Fund - First Eagle U.S. Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>020106 - Document - Risk/Return Summary {Unlabeled} - First Eagle Gold Fund - First Eagle Gold Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleGoldFundFirstEagleGoldFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Gold Fund - First Eagle Gold Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>020107 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Gold Fund - First Eagle Gold Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleGoldFundFirstEagleGoldFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Gold Fund - First Eagle Gold Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020108 - Document - Risk/Return Summary {Unlabeled} - First Eagle Global Income Builder Fund - First Eagle Global Income Builder Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleGlobalIncomeBuilderFundFirstEagleGlobalIncomeBuilderFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Global Income Builder Fund - First Eagle Global Income Builder Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>020109 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Global Income Builder Fund - First Eagle Global Income Builder Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleGlobalIncomeBuilderFundFirstEagleGlobalIncomeBuilderFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Global Income Builder Fund - First Eagle Global Income Builder Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>020110 - Document - Risk/Return Summary {Unlabeled} - First Eagle Rising Dividend Fund - First Eagle Rising Dividend Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleRisingDividendFundFirstEagleRisingDividendFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Rising Dividend Fund - First Eagle Rising Dividend Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>020111 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Rising Dividend Fund - First Eagle Rising Dividend Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleRisingDividendFundFirstEagleRisingDividendFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Rising Dividend Fund - First Eagle Rising Dividend Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>020112 - Document - Risk/Return Summary {Unlabeled} - First Eagle Small Cap Opportunity Fund - First Eagle Small Cap Opportunity Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleSmallCapOpportunityFundFirstEagleSmallCapOpportunityFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Small Cap Opportunity Fund - First Eagle Small Cap Opportunity Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>020113 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Small Cap Opportunity Fund - First Eagle Small Cap Opportunity Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleSmallCapOpportunityFundFirstEagleSmallCapOpportunityFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Small Cap Opportunity Fund - First Eagle Small Cap Opportunity Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>020114 - Document - Risk/Return Summary {Unlabeled} - First Eagle U.S. Smid Cap Opportunity Fund - First Eagle U.S. Smid Cap Opportunity Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleUSSmidCapOpportunityFundFirstEagleUSSmidCapOpportunityFund</Role>
      <ShortName>Risk/Return Summary- First Eagle U.S. Smid Cap Opportunity Fund - First Eagle U.S. Smid Cap Opportunity Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>020115 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle U.S. Smid Cap Opportunity Fund - First Eagle U.S. Smid Cap Opportunity Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleUSSmidCapOpportunityFundFirstEagleUSSmidCapOpportunityFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle U.S. Smid Cap Opportunity Fund - First Eagle U.S. Smid Cap Opportunity Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>020116 - Document - Risk/Return Summary {Unlabeled} - First Eagle Global Real Assets Fund - First Eagle Global Real Assets Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleGlobalRealAssetsFundFirstEagleGlobalRealAssetsFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Global Real Assets Fund - First Eagle Global Real Assets Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>020117 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Global Real Assets Fund - First Eagle Global Real Assets Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleGlobalRealAssetsFundFirstEagleGlobalRealAssetsFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Global Real Assets Fund - First Eagle Global Real Assets Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>020118 - Document - Risk/Return Summary {Unlabeled} - First Eagle High Yield Municipal Fund - First Eagle High Yield Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleHighYieldMunicipalFundFirstEagleHighYieldMunicipalFund</Role>
      <ShortName>Risk/Return Summary- First Eagle High Yield Municipal Fund - First Eagle High Yield Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>020119 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle High Yield Municipal Fund - First Eagle High Yield Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleHighYieldMunicipalFundFirstEagleHighYieldMunicipalFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle High Yield Municipal Fund - First Eagle High Yield Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>020120 - Document - Risk/Return Summary {Unlabeled} - First Eagle Short Duration High Yield Municipal Fund - First Eagle Short Duration High Yield Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleShortDurationHighYieldMunicipalFundFirstEagleShortDurationHighYieldMunicipalFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Short Duration High Yield Municipal Fund - First Eagle Short Duration High Yield Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>020121 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Short Duration High Yield Municipal Fund - First Eagle Short Duration High Yield Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleShortDurationHighYieldMunicipalFundFirstEagleShortDurationHighYieldMunicipalFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Short Duration High Yield Municipal Fund - First Eagle Short Duration High Yield Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>020122 - Document - Risk/Return Summary {Unlabeled} - First Eagle Core Plus Municipal Fund - First Eagle Core Plus Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DocumentRiskReturnSummaryUnlabeledFirstEagleCorePlusMunicipalFundFirstEagleCorePlusMunicipalFund</Role>
      <ShortName>Risk/Return Summary- First Eagle Core Plus Municipal Fund - First Eagle Core Plus Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="c115123_485bpos-ixbrl.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>020123 - Disclosure - Risk/Return Detail Data {Elements} - First Eagle Core Plus Municipal Fund - First Eagle Core Plus Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firsteagle.com/20251231/role/DisclosureRiskReturnDetailDataElementsFirstEagleCorePlusMunicipalFundFirstEagleCorePlusMunicipalFund</Role>
      <ShortName>Risk/Return Detail Data- First Eagle Core Plus Municipal Fund - First Eagle Core Plus Municipal Fund</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>36</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="485BPOS" isN1a="true" isOEF="true" isRRorOEF="true" isUsgaap="true" original="c115123_485bpos-ixbrl.htm">c115123_485bpos-ixbrl.htm</File>
    <File>ck0000906352-20251231.xsd</File>
    <File>ck0000906352-20251231_def.xml</File>
    <File>ck0000906352-20251231_lab.xml</File>
    <File>ck0000906352-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>c115123xgibfxbar.jpg</File>
    <File>c115123xglobalrealassetsxbar.jpg</File>
    <File>c115123xglobalxbar.jpg</File>
    <File>c115123xgoldxbar.jpg</File>
    <File>c115123xhymfxbar.jpg</File>
    <File>c115123xoverseasxbar.jpg</File>
    <File>c115123xrisingdividendxbar.jpg</File>
    <File>c115123xscofxbar.jpg</File>
    <File>c115123xsdhymfxbar.jpg</File>
    <File>c115123xusscofxbar.jpg</File>
    <File>c115123xusvaluexbar.jpg</File>
    <File>fexstackedpantonexbcxlogo.jpg</File>
    <File>fexstackedpantonexstatxlogo.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="6">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="1872">http://xbrl.sec.gov/oef/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
