<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>791</ContextCount>
  <ElementCount>34</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>168</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>3</UnitCount>
  <MyReports>
    <Report instance="johnson_ncsrs.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>030000 - Disclosure - Form N-CSR Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/NcsrCover</Role>
      <ShortName>Form N-CSR Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="johnson_ncsrs.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>030001 - Disclosure - Shareholder Report</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReport</Role>
      <ShortName>Shareholder Report</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="johnson_ncsrs.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>040010 - Disclosure - Shareholder Report, Line Graph (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReportLineGraphDetails</Role>
      <ShortName>Shareholder Report, Line Graph (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="johnson_ncsrs.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>040015 - Disclosure - Shareholder Report, Average Annual Return (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReportAverageAnnualReturnDetails</Role>
      <ShortName>Shareholder Report, Average Annual Return (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="johnson_ncsrs.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>040020 - Disclosure - Shareholder Report, Holdings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReportHoldingsDetails</Role>
      <ShortName>Shareholder Report, Holdings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>jmft-20260630.xsd</File>
    <File doctype="N-CSRS" isDefinitelyNotFs="true" isNcsr="true" isOEF="true" isRRorOEF="true" isUsgaap="true" original="johnson_ncsrs.htm">johnson_ncsrs.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>i0107f1c950bab0c5b08564c7.jpg</File>
    <File>i03381d86713003465e3c0a00.jpg</File>
    <File>i091ddebab4024ebb9ff21829.jpg</File>
    <File>i275881a30bf40b9976bd187a.jpg</File>
    <File>i28226cd1c7cdedb1b82e7196.jpg</File>
    <File>i3210df596948678450da9baf.jpg</File>
    <File>i36ba1433208654e437d7ddf2.jpg</File>
    <File>i44fd4c5891e60adf262fef63.jpg</File>
    <File>i4c4d468d49eb61fac465db9a.jpg</File>
    <File>i4fa226d5ff0db11bf5a8c2fe.jpg</File>
    <File>i5987901abb285bcbe9dbc360.jpg</File>
    <File>i5c0dadbe1bbb3baefe11d746.jpg</File>
    <File>i6225a4774f880fcd1a269963.jpg</File>
    <File>i6d8b80526801d5cb7d6bbc7f.jpg</File>
    <File>i72f4f017fdfb75f79e1f2aca.jpg</File>
    <File>i827e8b0603cdba17586a947a.jpg</File>
    <File>i85e680d530fa6505e80b06ec.jpg</File>
    <File>ia08f39f9cff631ecf310ff4c.jpg</File>
    <File>ia3fd48cc9a254d98d7f11355.jpg</File>
    <File>ia99b52a71f14664ad4e5ecdb.jpg</File>
    <File>iab2763aab909c470737100a7.jpg</File>
    <File>ib1fb6c127f53b8b905e7964f.jpg</File>
    <File>ib6619ffd793eea2ba943a721.jpg</File>
    <File>ib8a1bc244933f2bd302873fe.jpg</File>
    <File>ib95ae9ead87e6ca3b8c3ac62.jpg</File>
    <File>ib9cad484c3418b2777bc24b4.jpg</File>
    <File>ibfcc96df35db016efbd2b253.jpg</File>
    <File>ic68b2d8bff101837a97509ee.jpg</File>
    <File>id1eedb52b2f8d00b9280aee3.jpg</File>
    <File>id2e86ca30d785ede6087fba5.jpg</File>
    <File>id3cd57cdd134e4691742c509.jpg</File>
    <File>ie264227fcb531119da4fe11f.jpg</File>
    <File>iece8d24fc59f120d7231c2dc.jpg</File>
    <File>if20fd25abbdf354cd5d1b107.jpg</File>
    <File>ifc21f9e8ea27fb3db11e64ca.jpg</File>
    <File>logo.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="28">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="37">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="1070">http://xbrl.sec.gov/oef/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
