3.20.2 html 753 552 1 false 132 0 false 10 false false R1.htm 00090 - Document - Document And Entity Information Sheet http://flushingbank.com/role/DocumentDocumentAndEntityInformation Document And Entity Information Cover 1 false false R2.htm 00100 - Statement - Consolidated Statements of Financial Condition Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfFinancialCondition Consolidated Statements of Financial Condition Statements 2 false false R3.htm 00105 - Statement - Consolidated Statements of Financial Condition (Parentheticals) Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfFinancialConditionParentheticals Consolidated Statements of Financial Condition (Parentheticals) Statements 3 false false R4.htm 00200 - Statement - Consolidated Statements of Income Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfIncome Consolidated Statements of Income Statements 4 false false R5.htm 00300 - Statement - Consolidated Statements of Comprehensive Income Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfComprehensiveIncome Consolidated Statements of Comprehensive Income Statements 5 false false R6.htm 00305 - Statement - Consolidated Statements of Comprehensive Income (Parentheticals) Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfComprehensiveIncomeParentheticals Consolidated Statements of Comprehensive Income (Parentheticals) Statements 6 false false R7.htm 00400 - Statement - Consolidated Statements of Cash Flows Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows Statements 7 false false R8.htm 00500 - Statement - Consolidated Statements of Changes in Stockholders' Equity Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfChangesInStockholdersEquity Consolidated Statements of Changes in Stockholders' Equity Statements 8 false false R9.htm 00505 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) Sheet http://flushingbank.com/role/StatementConsolidatedStatementsOfChangesInStockholdersEquityParentheticals Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) Statements 9 false false R10.htm 10101 - Disclosure - Basis of Presentation Sheet http://flushingbank.com/role/DisclosureBasisOfPresentation Basis of Presentation Notes 10 false false R11.htm 10201 - Disclosure - Use of Estimates Sheet http://flushingbank.com/role/DisclosureUseOfEstimates Use of Estimates Notes 11 false false R12.htm 10301 - Disclosure - Earnings Per Share Sheet http://flushingbank.com/role/DisclosureEarningsPerShare Earnings Per Share Notes 12 false false R13.htm 10401 - Disclosure - Securities Sheet http://flushingbank.com/role/DisclosureSecurities Securities Notes 13 false false R14.htm 10501 - Disclosure - Loans Sheet http://flushingbank.com/role/DisclosureLoans Loans Notes 14 false false R15.htm 10601 - Disclosure - Loans Held for Sale Sheet http://flushingbank.com/role/DisclosureLoansHeldForSale Loans Held for Sale Notes 15 false false R16.htm 10701 - Disclosure - Other Real Estate Owned Sheet http://flushingbank.com/role/DisclosureOtherRealEstateOwned Other Real Estate Owned Notes 16 false false R17.htm 10801 - Disclosure - Leases Sheet http://flushingbank.com/role/DisclosureLeases Leases Notes 17 false false R18.htm 10901 - Disclosure - Stock-based Compensation Sheet http://flushingbank.com/role/DisclosureStockBasedCompensation Stock-based Compensation Notes 18 false false R19.htm 11001 - Disclosure - Pension and Other Postretirement Benefit Plans Sheet http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitPlans Pension and Other Postretirement Benefit Plans Notes 19 false false R20.htm 11101 - Disclosure - Fair Value of Financial Instruments Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstruments Fair Value of Financial Instruments Notes 20 false false R21.htm 11201 - Disclosure - Derivative Financial Instruments Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstruments Derivative Financial Instruments Notes 21 false false R22.htm 11301 - Disclosure - Income Taxes Sheet http://flushingbank.com/role/DisclosureIncomeTaxes Income Taxes Notes 22 false false R23.htm 11401 - Disclosure - Accumulated Other Comprehensive Income (Loss) Sheet http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss Accumulated Other Comprehensive Income (Loss) Notes 23 false false R24.htm 11501 - Disclosure - Regulatory Capital Sheet http://flushingbank.com/role/DisclosureRegulatoryCapital Regulatory Capital Notes 24 false false R25.htm 11601 - Disclosure - Subsequent Events Sheet http://flushingbank.com/role/DisclosureSubsequentEvents Subsequent Events Notes 25 false false R26.htm 11701 - Disclosure - New Authoritative Accounting Pronouncements Sheet http://flushingbank.com/role/DisclosureNewAuthoritativeAccountingPronouncements New Authoritative Accounting Pronouncements Notes 26 false false R27.htm 30303 - Disclosure - Earnings Per Share (Tables) Sheet http://flushingbank.com/role/DisclosureEarningsPerShareTables Earnings Per Share (Tables) Tables http://flushingbank.com/role/DisclosureEarningsPerShare 27 false false R28.htm 30403 - Disclosure - Securities (Tables) Sheet http://flushingbank.com/role/DisclosureSecuritiesTables Securities (Tables) Tables http://flushingbank.com/role/DisclosureSecurities 28 false false R29.htm 30503 - Disclosure - Loans (Tables) Sheet http://flushingbank.com/role/DisclosureLoansTables Loans (Tables) Tables http://flushingbank.com/role/DisclosureLoans 29 false false R30.htm 30603 - Disclosure - Loans Held for Sale (Tables) Sheet http://flushingbank.com/role/DisclosureLoansHeldForSaleTables Loans Held for Sale (Tables) Tables http://flushingbank.com/role/DisclosureLoansHeldForSale 30 false false R31.htm 30703 - Disclosure - Other Real Estate Owned (Tables) Sheet http://flushingbank.com/role/DisclosureOtherRealEstateOwnedTables Other Real Estate Owned (Tables) Tables http://flushingbank.com/role/DisclosureOtherRealEstateOwned 31 false false R32.htm 30803 - Disclosure - Leases (Tables) Sheet http://flushingbank.com/role/DisclosureLeasesTables Leases (Tables) Tables http://flushingbank.com/role/DisclosureLeases 32 false false R33.htm 30903 - Disclosure - Stock-based Compensation (Tables) Sheet http://flushingbank.com/role/DisclosureStockBasedCompensationTables Stock-based Compensation (Tables) Tables http://flushingbank.com/role/DisclosureStockBasedCompensation 33 false false R34.htm 31003 - Disclosure - Pension and Other Postretirement Benefit Plans (Tables) Sheet http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitPlansTables Pension and Other Postretirement Benefit Plans (Tables) Tables http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitPlans 34 false false R35.htm 31103 - Disclosure - Fair Value of Financial Instruments (Tables) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsTables Fair Value of Financial Instruments (Tables) Tables http://flushingbank.com/role/DisclosureFairValueOfFinancialInstruments 35 false false R36.htm 31203 - Disclosure - Derivative Financial Instruments (Tables) Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsTables Derivative Financial Instruments (Tables) Tables http://flushingbank.com/role/DisclosureDerivativeFinancialInstruments 36 false false R37.htm 31303 - Disclosure - Income Taxes (Tables) Sheet http://flushingbank.com/role/DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://flushingbank.com/role/DisclosureIncomeTaxes 37 false false R38.htm 31403 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Tables) Sheet http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables Accumulated Other Comprehensive Income (Loss) (Tables) Tables http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss 38 false false R39.htm 31503 - Disclosure - Regulatory Capital (Tables) Sheet http://flushingbank.com/role/DisclosureRegulatoryCapitalTables Regulatory Capital (Tables) Tables http://flushingbank.com/role/DisclosureRegulatoryCapital 39 false false R40.htm 40201 - Disclosure - Use of Estimates (Details) Sheet http://flushingbank.com/role/DisclosureUseOfEstimatesDetails Use of Estimates (Details) Details http://flushingbank.com/role/DisclosureUseOfEstimates 40 false false R41.htm 40301 - Disclosure - Earnings Per Share (Details) Sheet http://flushingbank.com/role/DisclosureEarningsPerShareDetails Earnings Per Share (Details) Details http://flushingbank.com/role/DisclosureEarningsPerShareTables 41 false false R42.htm 40302 - Disclosure - Earnings Per Share - Anti Dilutive (Details) Sheet http://flushingbank.com/role/DisclosureEarningsPerShareAntiDilutiveDetails Earnings Per Share - Anti Dilutive (Details) Details 42 false false R43.htm 40401 - Disclosure - Securities (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesDetails Securities (Details) Details http://flushingbank.com/role/DisclosureSecuritiesTables 43 false false R44.htm 40402 - Disclosure - Securities - Amortized Cost and Fair Value of Securities (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesAmortizedCostAndFairValueOfSecuritiesDetails Securities - Amortized Cost and Fair Value of Securities (Details) Details 44 false false R45.htm 40403 - Disclosure - Securities - Securities Available-for-sale and Held-to-maturity by Contractual Maturity (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesSecuritiesAvailableForSaleAndHeldToMaturityByContractualMaturityDetails Securities - Securities Available-for-sale and Held-to-maturity by Contractual Maturity (Details) Details 45 false false R46.htm 40404 - Disclosure - Securities - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesAvailableForSaleSecuritiesWithGrossUnrealizedLossesAndTheirFairValueDetails Securities - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (Details) Details 46 false false R47.htm 40405 - Disclosure - Securities - Allowance for credit losses for debt securities held-to-maturity (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesAllowanceForCreditLossesForDebtSecuritiesHeldToMaturityDetails Securities - Allowance for credit losses for debt securities held-to-maturity (Details) Details 47 false false R48.htm 40406 - Disclosure - Securities - Gross Gain (Loss) Realized From the Sale of Securities Available for Sale (Details) Sheet http://flushingbank.com/role/DisclosureSecuritiesGrossGainLossRealizedFromSaleOfSecuritiesAvailableForSaleDetails Securities - Gross Gain (Loss) Realized From the Sale of Securities Available for Sale (Details) Details 48 false false R49.htm 40501 - Disclosure - Loans and Allowance for Loan Losses (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesDetails Loans and Allowance for Loan Losses (Details) Details 49 false false R50.htm 40502 - Disclosure - Loans and Allowance for Loan Losses - Loans Modified and Classified as TDR (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesLoansModifiedAndClassifiedAsTdrDetails Loans and Allowance for Loan Losses - Loans Modified and Classified as TDR (Details) Details 50 false false R51.htm 40503 - Disclosure - Loans and Allowance for Loan Losses - Troubled Debt Restructurings That Are Performing (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesTroubledDebtRestructuringsThatArePerformingDetails Loans and Allowance for Loan Losses - Troubled Debt Restructurings That Are Performing (Details) Details 51 false false R52.htm 40504 - Disclosure - Loans and Allowance for Loan Losses - Troubled Debt Restructurings That Are Not Performing (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesTroubledDebtRestructuringsThatAreNotPerformingDetails Loans and Allowance for Loan Losses - Troubled Debt Restructurings That Are Not Performing (Details) Details 52 false false R53.htm 40505 - Disclosure - Loans and Allowance for Loan Losses - Non-performing Loans (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesNonPerformingLoansDetails Loans and Allowance for Loan Losses - Non-performing Loans (Details) Details 53 false false R54.htm 40506 - Disclosure - Loans and Allowance for Loan Losses - Foregone on Non-accrual Loans and Loans Classified as TDR (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesForegoneOnNonAccrualLoansAndLoansClassifiedAsTdrDetails Loans and Allowance for Loan Losses - Foregone on Non-accrual Loans and Loans Classified as TDR (Details) Details 54 false false R55.htm 40507 - Disclosure - Loans and Allowance for Loan Losses - Age Analysis of Recorded Investment in Loans (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesAgeAnalysisOfRecordedInvestmentInLoansDetails Loans and Allowance for Loan Losses - Age Analysis of Recorded Investment in Loans (Details) Details 55 false false R56.htm 40508 - Disclosure - Loans and Allowance for Loan Losses - Activity in the Allowance for Loan Losses (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesActivityInAllowanceForLoanLossesDetails Loans and Allowance for Loan Losses - Activity in the Allowance for Loan Losses (Details) Details 56 false false R57.htm 40509 - Disclosure - Loans and Allowance for Loan Losses - Non-Accrual at Amortized Cost (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesNonAccrualAtAmortizedCostDetails Loans and Allowance for Loan Losses - Non-Accrual at Amortized Cost (Details) Details 57 false false R58.htm 40510 - Disclosure - Loans and Allowance for Loan Losses - Risk category of our loan portfolio (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesRiskCategoryOfOurLoanPortfolioDetails Loans and Allowance for Loan Losses - Risk category of our loan portfolio (Details) Details 58 false false R59.htm 40511 - Disclosure - Loans and Allowance for Loan Losses - Loans Designated as Criticized or Classified (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesLoansDesignatedAsCriticizedOrClassifiedDetails Loans and Allowance for Loan Losses - Loans Designated as Criticized or Classified (Details) Details 59 false false R60.htm 40512 - Disclosure - Loans and Allowance for Loan Losses - Amortized Cost of Collateral (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesAmortizedCostOfCollateralDetails Loans and Allowance for Loan Losses - Amortized Cost of Collateral (Details) Details 60 false false R61.htm 40513 - Disclosure - Loans and Allowance for Loan Losses - Off-Balance Sheet Credit Losses (Details) Sheet http://flushingbank.com/role/DisclosureLoansAndAllowanceForLoanLossesOffBalanceSheetCreditLossesDetails Loans and Allowance for Loan Losses - Off-Balance Sheet Credit Losses (Details) Details 61 false false R62.htm 40601 - Disclosure - Loans Held for Sale (Details) Sheet http://flushingbank.com/role/DisclosureLoansHeldForSaleDetails Loans Held for Sale (Details) Details http://flushingbank.com/role/DisclosureLoansHeldForSaleTables 62 false false R63.htm 40602 - Disclosure - Loans Held for Sale - Delinquent and Non-performing Loans Sold During the Period Indicated (Details) Sheet http://flushingbank.com/role/DisclosureLoansHeldForSaleDelinquentAndNonPerformingLoansSoldDuringPeriodIndicatedDetails Loans Held for Sale - Delinquent and Non-performing Loans Sold During the Period Indicated (Details) Details 63 false false R64.htm 40701 - Disclosure - Other Real Estate Owned (Details) Sheet http://flushingbank.com/role/DisclosureOtherRealEstateOwnedDetails Other Real Estate Owned (Details) Details http://flushingbank.com/role/DisclosureOtherRealEstateOwnedTables 64 false false R65.htm 40702 - Disclosure - Other Real Estate Owned - Changes in Other Real Estate Owned (Details) Sheet http://flushingbank.com/role/DisclosureOtherRealEstateOwnedChangesInOtherRealEstateOwnedDetails Other Real Estate Owned - Changes in Other Real Estate Owned (Details) Details 65 false false R66.htm 40703 - Disclosure - Other Real Estate Owned - Gross Gains, Gross Losses and Write-downs of OREO (Details) Sheet http://flushingbank.com/role/DisclosureOtherRealEstateOwnedGrossGainsGrossLossesAndWriteDownsOfOreoDetails Other Real Estate Owned - Gross Gains, Gross Losses and Write-downs of OREO (Details) Details 66 false false R67.htm 40801 - Disclosure - Leases (Details) Sheet http://flushingbank.com/role/DisclosureLeasesDetails Leases (Details) Details http://flushingbank.com/role/DisclosureLeasesTables 67 false false R68.htm 40802 - Disclosure - Leases - Balance Sheet Disclosures and Components of Lease Expense (Details) Sheet http://flushingbank.com/role/DisclosureLeasesBalanceSheetDisclosuresAndComponentsOfLeaseExpenseDetails Leases - Balance Sheet Disclosures and Components of Lease Expense (Details) Details 68 false false R69.htm 40803 - Disclosure - Leases - Minimum Annual Rental Payments for Bank facilities Due Under Non-cancelable Leases (Details) Sheet http://flushingbank.com/role/DisclosureLeasesMinimumAnnualRentalPaymentsForBankFacilitiesDueUnderNonCancelableLeasesDetails Leases - Minimum Annual Rental Payments for Bank facilities Due Under Non-cancelable Leases (Details) Details 69 false false R70.htm 40901 - Disclosure - Stock-based Compensation (Details) Sheet http://flushingbank.com/role/DisclosureStockBasedCompensationDetails Stock-based Compensation (Details) Details http://flushingbank.com/role/DisclosureStockBasedCompensationTables 70 false false R71.htm 40902 - Disclosure - Stock-based Compensation - Restricted Stock Units (Details) Sheet http://flushingbank.com/role/DisclosureStockBasedCompensationRestrictedStockUnitsDetails Stock-based Compensation - Restricted Stock Units (Details) Details 71 false false R72.htm 40903 - Disclosure - Stock-based Compensation - Phantom Stock Plan (Details) Sheet http://flushingbank.com/role/DisclosureStockBasedCompensationPhantomStockPlanDetails Stock-based Compensation - Phantom Stock Plan (Details) Details 72 false false R73.htm 41001 - Disclosure - Pension and Other Postretirement Benefit Plans (Details) Sheet http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitPlansDetails Pension and Other Postretirement Benefit Plans (Details) Details http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitPlansTables 73 false false R74.htm 41002 - Disclosure - Pension and Other Postretirement Benefits - The Components of the Net Pension Expense (Details) Sheet http://flushingbank.com/role/DisclosurePensionAndOtherPostretirementBenefitsComponentsOfNetPensionExpenseDetails Pension and Other Postretirement Benefits - The Components of the Net Pension Expense (Details) Details 74 false false R75.htm 41101 - Disclosure - Fair Value of Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsDetails Fair Value of Financial Instruments (Details) Details http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsTables 75 false false R76.htm 41102 - Disclosure - Fair Value of Financial Instruments - Financial Assets and Liabilities Reported Under the Fair Value Option (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsFinancialAssetsAndLiabilitiesReportedUnderFairValueOptionDetails Fair Value of Financial Instruments - Financial Assets and Liabilities Reported Under the Fair Value Option (Details) Details 76 false false R77.htm 41103 - Disclosure - Fair Value of Financial Instruments - Fair Value Measured on a Recurring Basis (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsFairValueMeasuredOnRecurringBasisDetails Fair Value of Financial Instruments - Fair Value Measured on a Recurring Basis (Details) Details 77 false false R78.htm 41104 - Disclosure - Fair Value of Financial Instruments - Assets and Liabilities Carried at Fair Value on a Recurring Basis, Classified Within Level 3 (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsAssetsAndLiabilitiesCarriedAtFairValueOnRecurringBasisClassifiedWithinLevel3Details Fair Value of Financial Instruments - Assets and Liabilities Carried at Fair Value on a Recurring Basis, Classified Within Level 3 (Details) Details 78 false false R79.htm 41105 - Disclosure - Fair Value of Financial Instruments - Quantitative Information About Recurring Level 3 Fair Value of Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsQuantitativeInformationAboutRecurringLevel3FairValueOfFinancialInstrumentsDetails Fair Value of Financial Instruments - Quantitative Information About Recurring Level 3 Fair Value of Financial Instruments (Details) Details 79 false false R80.htm 41106 - Disclosure - Fair Value of Financial Instruments - Assets and Liabilities Carried at Fair Value on a Non-recurring Basis, Fair Value (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsAssetsAndLiabilitiesCarriedAtFairValueOnNonRecurringBasisFairValueDetails Fair Value of Financial Instruments - Assets and Liabilities Carried at Fair Value on a Non-recurring Basis, Fair Value (Details) Details 80 false false R81.htm 41107 - Disclosure - Fair Value of Financial Instruments - Quantitative Information About Non-recurring Level 3 Fair Value of Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsQuantitativeInformationAboutNonRecurringLevel3FairValueOfFinancialInstrumentsDetails Fair Value of Financial Instruments - Quantitative Information About Non-recurring Level 3 Fair Value of Financial Instruments (Details) Details 81 false false R82.htm 41108 - Disclosure - Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Selected Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureFairValueOfFinancialInstrumentsCarryingAmountsAndEstimatedFairValuesOfSelectedFinancialInstrumentsDetails Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Selected Financial Instruments (Details) Details 82 false false R83.htm 41201 - Disclosure - Derivative Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsDetails Derivative Financial Instruments (Details) Details http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsTables 83 false false R84.htm 41202 - Disclosure - Derivative Financial Instruments - Derivative Financial Instruments (Details) Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsDerivativeFinancialInstrumentsDetails Derivative Financial Instruments - Derivative Financial Instruments (Details) Details 84 false false R85.htm 41203 - Disclosure - Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Statements of Income (Details) Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfDerivativeInstrumentsOnConsolidatedStatementsOfIncomeDetails Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Statements of Income (Details) Details 85 false false R86.htm 41204 - Disclosure - Derivative Financial Instruments - Effect of Master Netting Arrangements on Derivative Assets and Liabilities in the Consolidated Statements of Condition (Details) Sheet http://flushingbank.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfMasterNettingArrangementsOnDerivativeAssetsAndLiabilitiesInConsolidatedStatementsOfConditionDetails Derivative Financial Instruments - Effect of Master Netting Arrangements on Derivative Assets and Liabilities in the Consolidated Statements of Condition (Details) Details 86 false false R87.htm 41301 - Disclosure - Income Taxes - Income Tax Provisions (Details) Sheet http://flushingbank.com/role/DisclosureIncomeTaxesIncomeTaxProvisionsDetails Income Taxes - Income Tax Provisions (Details) Details 87 false false R88.htm 41401 - Disclosure - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income by Component (Details) Sheet http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossChangesInAccumulatedOtherComprehensiveIncomeByComponentDetails Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income by Component (Details) Details http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables 88 false false R89.htm 41402 - Disclosure - Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) Sheet http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossAmountsReclassifiedOutOfAccumulatedOtherComprehensiveIncomeLossDetails Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) Details http://flushingbank.com/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables 89 false false R90.htm 41501 - Disclosure - Regulatory Capital (Details) Sheet http://flushingbank.com/role/DisclosureRegulatoryCapitalDetails Regulatory Capital (Details) Details http://flushingbank.com/role/DisclosureRegulatoryCapitalTables 90 false false R91.htm 41502 - Disclosure - Regulatory Capital - Summary of the Bank's Compliance (Details) Sheet http://flushingbank.com/role/DisclosureRegulatoryCapitalSummaryOfBankSComplianceDetails Regulatory Capital - Summary of the Bank's Compliance (Details) Details 91 false false R92.htm 41601 - Disclosure - Subsequent Events (Details) Sheet http://flushingbank.com/role/DisclosureSubsequentEventsDetails Subsequent Events (Details) Details http://flushingbank.com/role/DisclosureSubsequentEvents 92 false false R93.htm 41701 - Disclosure - New Authoritative Accounting Pronouncements (Details) Sheet http://flushingbank.com/role/DisclosureNewAuthoritativeAccountingPronouncementsDetails New Authoritative Accounting Pronouncements (Details) Details 93 false false All Reports Book All Reports ffic-20200930x10q.htm ffic-20200930.xsd ffic-20200930_cal.xml ffic-20200930_def.xml ffic-20200930_lab.xml ffic-20200930_pre.xml ffic-20200930xex31d1.htm ffic-20200930xex31d2.htm ffic-20200930xex32d1.htm ffic-20200930xex32d2.htm http://xbrl.sec.gov/dei/2019-01-31 http://fasb.org/srt/2019-01-31 http://fasb.org/us-gaap/2019-01-31 true true