<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.2.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>37</ContextCount>
  <ElementCount>90</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>30</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000000 - Document - Document and Entity Information {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.FederatedInvestors.com/role/DocumentDocumentandEntityInformationElements</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory></MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>000019 - Disclosure - Risk/Return Detail Data {Elements} - Federated Hermes Michigan Intermediate Municipal Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.FederatedInvestors.com/role/DisclosureRiskReturnDetailDataElementsFederatedHermesMichiganIntermediateMunicipalFund</Role>
      <ShortName>Risk/Return Detail Data- Federated Hermes Michigan Intermediate Municipal Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>000029 - Disclosure - Risk/Return Detail Data {Elements} - Federated Hermes Municipal High Yield Advantage Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.FederatedInvestors.com/role/DisclosureRiskReturnDetailDataElementsFederatedHermesMunicipalHighYieldAdvantageFund</Role>
      <ShortName>Risk/Return Detail Data- Federated Hermes Municipal High Yield Advantage Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>000039 - Disclosure - Risk/Return Detail Data {Elements} - Federated Hermes Ohio Municipal Income Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.FederatedInvestors.com/role/DisclosureRiskReturnDetailDataElementsFederatedHermesOhioMunicipalIncomeFund</Role>
      <ShortName>Risk/Return Detail Data- Federated Hermes Ohio Municipal Income Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>000049 - Disclosure - Risk/Return Detail Data {Elements} - Federated Hermes Pennsylvania Municipal Income Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.FederatedInvestors.com/role/DisclosureRiskReturnDetailDataElementsFederatedHermesPennsylvaniaMunicipalIncomeFund</Role>
      <ShortName>Risk/Return Detail Data- Federated Hermes Pennsylvania Municipal Income Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="msit558-form.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>040000 - Disclosure - Risk/Return Detail Data {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/RiskReturnDetailData</Role>
      <ShortName>Risk/Return Detail Data</ShortName>
      <MenuCategory></MenuCategory>
      <Position>6</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Warning">[ix-0514-Hidden-Fact-Eligible-For-Transform] WARN: 77 fact(s) appearing in ix:hidden were eligible for transformation: rr:ExpenseExampleNoRedemptionYear01, rr:ExpenseExampleNoRedemptionYear03, rr:ExpenseExampleNoRedemptionYear05, rr:ExpenseExampleNoRedemptionYear10, rr:ExpenseExampleYear01, rr:ExpenseExampleYear03, rr:ExpenseExampleYear05, rr:ExpenseExampleYear10, rr:HighestQuarterlyReturnLabel, rr:LowestQuarterlyReturnLabel, rr:ProspectusDate, rr:YearToDateReturnLabel -  msit558-form.htm 17, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145</Log>
  </Logs>
  <InputFiles>
    <File doctype="485BPOS" original="msit558-form.htm">msit558-form.htm</File>
    <File>exhibit28-a.htm</File>
    <File>exhibit28-g.htm</File>
    <File>exhibit28-h1b.htm</File>
    <File>exhibit28-h1c.htm</File>
    <File>exhibit28-h2b.htm</File>
    <File>exhibit28-h3.htm</File>
    <File>exhibit28-h4.htm</File>
    <File>exhibit28-j.htm</File>
    <File>exhibit28-n.htm</File>
    <File>exhibit28-p.htm</File>
    <File>fhmsit-20221026.xsd</File>
    <File>fhmsit-20221026_cal.xml</File>
    <File>fhmsit-20221026_def.xml</File>
    <File>fhmsit-20221026_lab.xml</File>
    <File>fhmsit-20221026_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>fhilogok11p_2.jpg</File>
    <File>fhmimfprog0138901a_8.jpg</File>
    <File>fmhyafpro35400_6.jpg</File>
    <File>img234b97891.gif</File>
    <File>img2a7047cb1.gif</File>
    <File>img3589a9ea1.gif</File>
    <File>img73df922f1.gif</File>
    <File>img9743d06e1.gif</File>
    <File>imgb9668b1c1.gif</File>
    <File>imgda1910ba1.gif</File>
    <File>imgf675ebad1.gif</File>
    <File>ohmifpro0090702af_4.jpg</File>
    <File>pamifprog0057702_4.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="20">http://xbrl.sec.gov/dei/2021</BaseTaxonomy>
    <BaseTaxonomy items="535">http://xbrl.sec.gov/rr/2021</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
