<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Version>2.4.0.8</Version>
  <ProcessingTime />
  <ReportFormat>HtmlAndXml</ReportFormat>
  <ContextCount>554</ContextCount>
  <ElementCount>460</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>136</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Disclosure - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <XmlFileName>R1.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Consolidated Statements of Financial Condition (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ConsolidatedBalanceSheet</Role>
      <ShortName>Consolidated Statements of Financial Condition (Unaudited)</ShortName>
      <XmlFileName>R2.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Consolidated Statements of Financial Condition (Unaudited) (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ConsolidatedBalanceSheet_Parentheticals</Role>
      <ShortName>Consolidated Statements of Financial Condition (Unaudited) (Parentheticals)</ShortName>
      <XmlFileName>R3.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Consolidated Statements of Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ConsolidatedIncomeStatement</Role>
      <ShortName>Consolidated Statements of Income (Unaudited)</ShortName>
      <XmlFileName>R4.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ConsolidatedComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <XmlFileName>R5.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ConsolidatedCashFlow</Role>
      <ShortName>Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <XmlFileName>R6.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Statement - Consolidated Statements of Changes in Stockholders’ Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ShareholdersEquityType1</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders’ Equity (Unaudited)</ShortName>
      <XmlFileName>R7.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Statement - Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ShareholdersEquityType1_Parentheticals</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) (Parentheticals)</ShortName>
      <XmlFileName>R8.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>008 - Disclosure - Note 1 - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note1BasisofPresentation</Role>
      <ShortName>Note 1 - Basis of Presentation</ShortName>
      <XmlFileName>R9.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>009 - Disclosure - Note 2 - Use of Estimates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note2UseofEstimates</Role>
      <ShortName>Note 2 - Use of Estimates</ShortName>
      <XmlFileName>R10.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010 - Disclosure - Note 3 - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note3EarningsPerShare</Role>
      <ShortName>Note 3 - Earnings Per Share</ShortName>
      <XmlFileName>R11.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>011 - Disclosure - Note 4 - Debt and Equity Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note4DebtandEquitySecurities</Role>
      <ShortName>Note 4 - Debt and Equity Securities</ShortName>
      <XmlFileName>R12.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>012 - Disclosure - Note 5 - Loans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note5Loans</Role>
      <ShortName>Note 5 - Loans</ShortName>
      <XmlFileName>R13.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>013 - Disclosure - Note 6 - Loans held for sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note6Loansheldforsale</Role>
      <ShortName>Note 6 - Loans held for sale</ShortName>
      <XmlFileName>R14.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>014 - Disclosure - Note 7 - Other Real Estate Owned</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note7OtherRealEstateOwned</Role>
      <ShortName>Note 7 - Other Real Estate Owned</ShortName>
      <XmlFileName>R15.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>015 - Disclosure - Note 8 - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note8StockBasedCompensation</Role>
      <ShortName>Note 8 - Stock-Based Compensation</ShortName>
      <XmlFileName>R16.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>016 - Disclosure - Note 9 - Pension and Other Postretirement Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note9PensionandOtherPostretirementBenefitPlans</Role>
      <ShortName>Note 9 - Pension and Other Postretirement Benefit Plans</ShortName>
      <XmlFileName>R17.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>017 - Disclosure - Note 10 - Fair Value of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note10FairValueofFinancialInstruments</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments</ShortName>
      <XmlFileName>R18.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>018 - Disclosure - Note 11 - Derivative Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note11DerivativeFinancialInstruments</Role>
      <ShortName>Note 11 - Derivative Financial Instruments</ShortName>
      <XmlFileName>R19.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>019 - Disclosure - Note 12 - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note12IncomeTaxes</Role>
      <ShortName>Note 12 - Income Taxes</ShortName>
      <XmlFileName>R20.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020 - Disclosure - Note 13 - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note13AccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Note 13 - Accumulated Other Comprehensive Income</ShortName>
      <XmlFileName>R21.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>021 - Disclosure - Note 14 - Regulatory</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note14Regulatory</Role>
      <ShortName>Note 14 - Regulatory</ShortName>
      <XmlFileName>R22.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>022 - Disclosure - Note 15 - New Authoritative Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note15NewAuthoritativeAccountingPronouncements</Role>
      <ShortName>Note 15 - New Authoritative Accounting Pronouncements</ShortName>
      <XmlFileName>R23.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>023 - Disclosure - Note 3 - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note3EarningsPerShareTables</Role>
      <ShortName>Note 3 - Earnings Per Share (Tables)</ShortName>
      <XmlFileName>R24.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>024 - Disclosure - Note 4 - Debt and Equity Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note4DebtandEquitySecuritiesTables</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Tables)</ShortName>
      <XmlFileName>R25.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>025 - Disclosure - Note 5 - Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note5LoansTables</Role>
      <ShortName>Note 5 - Loans (Tables)</ShortName>
      <XmlFileName>R26.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>026 - Disclosure - Note 6 - Loans held for sale (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note6LoansheldforsaleTables</Role>
      <ShortName>Note 6 - Loans held for sale (Tables)</ShortName>
      <XmlFileName>R27.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>027 - Disclosure - Note 7 - Other Real Estate Owned (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note7OtherRealEstateOwnedTables</Role>
      <ShortName>Note 7 - Other Real Estate Owned (Tables)</ShortName>
      <XmlFileName>R28.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>028 - Disclosure - Note 8 - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note8StockBasedCompensationTables</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Tables)</ShortName>
      <XmlFileName>R29.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>029 - Disclosure - Note 9 - Pension and Other Postretirement Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note9PensionandOtherPostretirementBenefitPlansTables</Role>
      <ShortName>Note 9 - Pension and Other Postretirement Benefit Plans (Tables)</ShortName>
      <XmlFileName>R30.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>030 - Disclosure - Note 10 - Fair Value of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note10FairValueofFinancialInstrumentsTables</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Tables)</ShortName>
      <XmlFileName>R31.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>031 - Disclosure - Note 11 - Derivative Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note11DerivativeFinancialInstrumentsTables</Role>
      <ShortName>Note 11 - Derivative Financial Instruments (Tables)</ShortName>
      <XmlFileName>R32.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>032 - Disclosure - Note 12 - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note12IncomeTaxesTables</Role>
      <ShortName>Note 12 - Income Taxes (Tables)</ShortName>
      <XmlFileName>R33.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>033 - Disclosure - Note 13 - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note13AccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Note 13 - Accumulated Other Comprehensive Income (Tables)</ShortName>
      <XmlFileName>R34.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>034 - Disclosure - Note 14 - Regulatory (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note14RegulatoryTables</Role>
      <ShortName>Note 14 - Regulatory (Tables)</ShortName>
      <XmlFileName>R35.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>035 - Disclosure - Note 3 - Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note3EarningsPerShareDetails</Role>
      <ShortName>Note 3 - Earnings Per Share (Details)</ShortName>
      <XmlFileName>R36.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>036 - Disclosure - Note 3 - Earnings Per Share (Details) - Earnings per common share:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/EarningspercommonshareTable</Role>
      <ShortName>Note 3 - Earnings Per Share (Details) - Earnings per common share:</ShortName>
      <XmlFileName>R37.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>037 - Disclosure - Note 4 - Debt and Equity Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note4DebtandEquitySecuritiesDetails</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details)</ShortName>
      <XmlFileName>R38.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>038 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Securities available for sale:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/SecuritiesavailableforsaleTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Securities available for sale:</ShortName>
      <XmlFileName>R39.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>039 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Available for sale securities with gross unrealized losses and their fair value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/AvailableforsalesecuritieswithgrossunrealizedlossesandtheirfairvalueTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Available for sale securities with gross unrealized losses and their fair value</ShortName>
      <XmlFileName>R40.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>040 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Trust preferred issues:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/TrustpreferredissuesTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Trust preferred issues:</ShortName>
      <XmlFileName>R41.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>041 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Collateralized mortgage obligations:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/CollateralizedmortgageobligationsTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Collateralized mortgage obligations:</ShortName>
      <XmlFileName>R42.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>042 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Gross unrealized losses recorded in AOCI:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/GrossunrealizedlossesrecordedinAOCITable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Gross unrealized losses recorded in AOCI:</ShortName>
      <XmlFileName>R43.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>043 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Credit loss component recognized in earnings on debt securities:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/CreditlosscomponentrecognizedinearningsondebtsecuritiesTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Credit loss component recognized in earnings on debt securities:</ShortName>
      <XmlFileName>R44.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>044 - Disclosure - Note 4 - Debt and Equity Securities (Details) - Securities available for sale by contractual maturity:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/SecuritiesavailableforsalebycontractualmaturityTable</Role>
      <ShortName>Note 4 - Debt and Equity Securities (Details) - Securities available for sale by contractual maturity:</ShortName>
      <XmlFileName>R45.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>045 - Disclosure - Note 5 - Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note5LoansDetails</Role>
      <ShortName>Note 5 - Loans (Details)</ShortName>
      <XmlFileName>R46.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>046 - Disclosure - Note 5 - Loans (Details) - Loans modified and classified as TDR:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/LoansmodifiedandclassifiedasTDRTable</Role>
      <ShortName>Note 5 - Loans (Details) - Loans modified and classified as TDR:</ShortName>
      <XmlFileName>R47.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>047 - Disclosure - Note 5 - Loans (Details) - Troubled debt restructurings that are performing according to their restructured terms:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/TroubleddebtrestructuringsthatareperformingaccordingtotheirrestructuredtermsTable</Role>
      <ShortName>Note 5 - Loans (Details) - Troubled debt restructurings that are performing according to their restructured terms:</ShortName>
      <XmlFileName>R48.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>048 - Disclosure - Note 5 - Loans (Details) - Troubled debt restructurings that are not performing according to their restructured terms:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/TroubleddebtrestructuringsthatarenotperformingaccordingtotheirrestructuredtermsTable</Role>
      <ShortName>Note 5 - Loans (Details) - Troubled debt restructurings that are not performing according to their restructured terms:</ShortName>
      <XmlFileName>R49.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>049 - Disclosure - Note 5 - Loans (Details) - Non-performing loans:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/NonperformingloansTable</Role>
      <ShortName>Note 5 - Loans (Details) - Non-performing loans:</ShortName>
      <XmlFileName>R50.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>050 - Disclosure - Note 5 - Loans (Details) - Summary of interest foregone on non-accrual loans and loans classified as TDR:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/SummaryofinterestforegoneonnonaccrualloansandloansclassifiedasTDRTable</Role>
      <ShortName>Note 5 - Loans (Details) - Summary of interest foregone on non-accrual loans and loans classified as TDR:</ShortName>
      <XmlFileName>R51.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>051 - Disclosure - Note 5 - Loans (Details) - Age analysis of recorded investment in loans:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/AgeanalysisofrecordedinvestmentinloansTable</Role>
      <ShortName>Note 5 - Loans (Details) - Age analysis of recorded investment in loans:</ShortName>
      <XmlFileName>R52.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>052 - Disclosure - Note 5 - Loans (Details) - Activity in the allowance for loan losses:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ActivityintheallowanceforloanlossesTable</Role>
      <ShortName>Note 5 - Loans (Details) - Activity in the allowance for loan losses:</ShortName>
      <XmlFileName>R53.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>053 - Disclosure - Note 5 - Loans (Details) - Impaired loans:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ImpairedloansTable</Role>
      <ShortName>Note 5 - Loans (Details) - Impaired loans:</ShortName>
      <XmlFileName>R54.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>054 - Disclosure - Note 5 - Loans (Details) - Loans designated as Criticized or Classified:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/LoansdesignatedasCriticizedorClassifiedTable</Role>
      <ShortName>Note 5 - Loans (Details) - Loans designated as Criticized or Classified:</ShortName>
      <XmlFileName>R55.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>055 - Disclosure - Note 5 - Loans (Details) - Allowance for loan losses:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/AllowanceforloanlossesTable</Role>
      <ShortName>Note 5 - Loans (Details) - Allowance for loan losses:</ShortName>
      <XmlFileName>R56.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>056 - Disclosure - Note 5 - Loans (Details) - Net loan charge-offs:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/NetloanchargeoffsTable</Role>
      <ShortName>Note 5 - Loans (Details) - Net loan charge-offs:</ShortName>
      <XmlFileName>R57.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>057 - Disclosure - Note 6 - Loans held for sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note6LoansheldforsaleDetails</Role>
      <ShortName>Note 6 - Loans held for sale (Details)</ShortName>
      <XmlFileName>R58.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>058 - Disclosure - Note 6 - Loans held for sale (Details) - Loans held for sale at the periods presented:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/LoansheldforsaleattheperiodspresentedTable</Role>
      <ShortName>Note 6 - Loans held for sale (Details) - Loans held for sale at the periods presented:</ShortName>
      <XmlFileName>R59.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>059 - Disclosure - Note 6 - Loans held for sale (Details) - Delinquent and non-performing loans sold during the period indicated:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/DelinquentandnonperformingloanssoldduringtheperiodindicatedTable</Role>
      <ShortName>Note 6 - Loans held for sale (Details) - Delinquent and non-performing loans sold during the period indicated:</ShortName>
      <XmlFileName>R60.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>060 - Disclosure - Note 7 - Other Real Estate Owned (Details) - Changes in Other Real Estate Owned (“OREO”):</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ChangesinOtherRealEstateOwnedOREOTable</Role>
      <ShortName>Note 7 - Other Real Estate Owned (Details) - Changes in Other Real Estate Owned (“OREO”):</ShortName>
      <XmlFileName>R61.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>061 - Disclosure - Note 7 - Other Real Estate Owned (Details) - Gross gains, gross losses and write-downs of OREO:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/GrossgainsgrosslossesandwritedownsofOREOTable</Role>
      <ShortName>Note 7 - Other Real Estate Owned (Details) - Gross gains, gross losses and write-downs of OREO:</ShortName>
      <XmlFileName>R62.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>062 - Disclosure - Note 8 - Stock-Based Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note8StockBasedCompensationDetails</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Details)</ShortName>
      <XmlFileName>R63.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>063 - Disclosure - Note 8 - Stock-Based Compensation (Details) - Full value awards:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/FullvalueawardsTable</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Details) - Full value awards:</ShortName>
      <XmlFileName>R64.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>064 - Disclosure - Note 8 - Stock-Based Compensation (Details) - Non-full value awards:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/NonfullvalueawardsTable</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Details) - Non-full value awards:</ShortName>
      <XmlFileName>R65.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>065 - Disclosure - Note 8 - Stock-Based Compensation (Details) - Stock options exercised:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/StockoptionsexercisedTable</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Details) - Stock options exercised:</ShortName>
      <XmlFileName>R66.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>066 - Disclosure - Note 8 - Stock-Based Compensation (Details) - Phantom Stock Plan:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/PhantomStockPlanTable</Role>
      <ShortName>Note 8 - Stock-Based Compensation (Details) - Phantom Stock Plan:</ShortName>
      <XmlFileName>R67.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>067 - Disclosure - Note 9 - Pension and Other Postretirement Benefit Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note9PensionandOtherPostretirementBenefitPlansDetails</Role>
      <ShortName>Note 9 - Pension and Other Postretirement Benefit Plans (Details)</ShortName>
      <XmlFileName>R68.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>068 - Disclosure - Note 9 - Pension and Other Postretirement Benefit Plans (Details) - Components of net expense for pension and other postretirement benefit plans:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ComponentsofnetexpenseforpensionandotherpostretirementbenefitplansTable</Role>
      <ShortName>Note 9 - Pension and Other Postretirement Benefit Plans (Details) - Components of net expense for pension and other postretirement benefit plans:</ShortName>
      <XmlFileName>R69.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>069 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note10FairValueofFinancialInstrumentsDetails</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details)</ShortName>
      <XmlFileName>R70.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>070 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Financial assets and liabilities reported under the fair value option:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/FinancialassetsandliabilitiesreportedunderthefairvalueoptionTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Financial assets and liabilities reported under the fair value option:</ShortName>
      <XmlFileName>R71.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>071 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Fair value measured on a non-recurring basis:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/FairvaluemeasuredonanonrecurringbasisTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Fair value measured on a non-recurring basis:</ShortName>
      <XmlFileName>R72.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>072 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Level 3 fair value reconciliation:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Level3fairvaluereconciliationTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Level 3 fair value reconciliation:</ShortName>
      <XmlFileName>R73.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>073 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Quantitative information about recurring Level 3 fair value of financial instruments and the fair value measurements:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/QuantitativeinformationaboutrecurringLevel3fairvalueoffinancialinstrumentsandthefairvaluemeasurementsTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Quantitative information about recurring Level 3 fair value of financial instruments and the fair value measurements:</ShortName>
      <XmlFileName>R74.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>074 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Fair value measured on a non-recurring basis:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/FairvaluemeasuredonanonrecurringbasisTable0</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Fair value measured on a non-recurring basis:</ShortName>
      <XmlFileName>R75.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>075 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Quantitative information about non-recurring Level 3 fair value of financial instruments and the fair value measurements:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/QuantitativeinformationaboutnonrecurringLevel3fairvalueoffinancialinstrumentsandthefairvaluemeasurementsTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Quantitative information about non-recurring Level 3 fair value of financial instruments and the fair value measurements:</ShortName>
      <XmlFileName>R76.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>076 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details) - Carrying amounts and estimated fair values of selected financial instruments:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/CarryingamountsandestimatedfairvaluesofselectedfinancialinstrumentsTable</Role>
      <ShortName>Note 10 - Fair Value of Financial Instruments (Details) - Carrying amounts and estimated fair values of selected financial instruments:</ShortName>
      <XmlFileName>R77.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>077 - Disclosure - Note 11 - Derivative Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note11DerivativeFinancialInstrumentsDetails</Role>
      <ShortName>Note 11 - Derivative Financial Instruments (Details)</ShortName>
      <XmlFileName>R78.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>078 - Disclosure - Note 11 - Derivative Financial Instruments (Details) - Derivative financial instruments:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/DerivativefinancialinstrumentsTable</Role>
      <ShortName>Note 11 - Derivative Financial Instruments (Details) - Derivative financial instruments:</ShortName>
      <XmlFileName>R79.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>079 - Disclosure - Note 11 - Derivative Financial Instruments (Details) - Effect of derivative instruments on income:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/EffectofderivativeinstrumentsonincomeTable</Role>
      <ShortName>Note 11 - Derivative Financial Instruments (Details) - Effect of derivative instruments on income:</ShortName>
      <XmlFileName>R80.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>080 - Disclosure - Note 12 - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note12IncomeTaxesDetails</Role>
      <ShortName>Note 12 - Income Taxes (Details)</ShortName>
      <XmlFileName>R81.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>081 - Disclosure - Note 12 - Income Taxes (Details) - Income tax provisions:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/IncometaxprovisionsTable</Role>
      <ShortName>Note 12 - Income Taxes (Details) - Income tax provisions:</ShortName>
      <XmlFileName>R82.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>082 - Disclosure - Note 12 - Income Taxes (Details) - Effective income tax rate reconciliation:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/EffectiveincometaxratereconciliationTable</Role>
      <ShortName>Note 12 - Income Taxes (Details) - Effective income tax rate reconciliation:</ShortName>
      <XmlFileName>R83.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>083 - Disclosure - Note 13 - Accumulated Other Comprehensive Income (Details) - Changes in accumulated other comprehensive income by component:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/ChangesinaccumulatedothercomprehensiveincomebycomponentTable</Role>
      <ShortName>Note 13 - Accumulated Other Comprehensive Income (Details) - Changes in accumulated other comprehensive income by component:</ShortName>
      <XmlFileName>R84.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>084 - Disclosure - Note 13 - Accumulated Other Comprehensive Income (Details) - Significant amounts reclassified out of accumulated other comprehensive income by component:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/SignificantamountsreclassifiedoutofaccumulatedothercomprehensiveincomebycomponentTable</Role>
      <ShortName>Note 13 - Accumulated Other Comprehensive Income (Details) - Significant amounts reclassified out of accumulated other comprehensive income by component:</ShortName>
      <XmlFileName>R85.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>085 - Disclosure - Note 14 - Regulatory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/Note14RegulatoryDetails</Role>
      <ShortName>Note 14 - Regulatory (Details)</ShortName>
      <XmlFileName>R86.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>086 - Disclosure - Note 14 - Regulatory (Details) - Summary of the Bank's compliance:</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://flushingbank.com/role/SummaryoftheBankscomplianceTable</Role>
      <ShortName>Note 14 - Regulatory (Details) - Summary of the Bank's compliance:</ShortName>
      <XmlFileName>R87.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element ffic_FinancialAssetsAtFairValueOption had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element ffic_FinancialLiabilitiesAtFairValueOption had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element ffic_MortgageBackedSecuritiesAvailableForSaleAmortizedCost had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_DefinedBenefitPlanContributionsByEmployer had a mix of decimals attribute values: -5 0.</Log>
    <Log type="Info">Element us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized had a mix of decimals attribute values: -5 0.</Log>
    <Log type="Info">Element us-gaap_MortgageBackedSecuritiesAvailableForSaleFairValueDisclosure had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_ShareBasedCompensation had a mix of decimals attribute values: -3 0.</Log>
    <Log type="Info">'Monetary' elements on report '037 - Disclosure - Note 4 - Debt and Equity Securities (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '045 - Disclosure - Note 5 - Loans (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '057 - Disclosure - Note 6 - Loans held for sale (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '067 - Disclosure - Note 9 - Pension and Other Postretirement Benefit Plans (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '069 - Disclosure - Note 10 - Fair Value of Financial Instruments (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '077 - Disclosure - Note 11 - Derivative Financial Instruments (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 001 - Statement - Consolidated Statements of Financial Condition (Unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Jun. 30, 2012'</Log>
    <Log type="Info">Process Flow-Through: 002 - Statement - Consolidated Statements of Financial Condition (Unaudited) (Parentheticals)</Log>
    <Log type="Info">Process Flow-Through: 003 - Statement - Consolidated Statements of Income (Unaudited)</Log>
    <Log type="Info">Process Flow-Through: 004 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</Log>
    <Log type="Info">Process Flow-Through: 005 - Statement - Consolidated Statements of Cash Flows (Unaudited)</Log>
    <Log type="Info">Process Flow-Through: 007 - Statement - Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) (Parentheticals)</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2013'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2012'</Log>
  </Logs>
  <InputFiles>
    <File>ffic-20130630.xml</File>
    <File>ffic-20130630.xsd</File>
    <File>ffic-20130630_cal.xml</File>
    <File>ffic-20130630_def.xml</File>
    <File>ffic-20130630_lab.xml</File>
    <File>ffic-20130630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
