Debt Disclosure [Abstract] Subordinated Debentures and Subordinated Notes Payable Debt Disclosure [Text Block] Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plan Pension Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Total pension plan assets Defined Benefit Plan, Fair Value of Plan Assets Pension liability Liability, Defined Benefit Pension Plan Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Mortgage-backed securities Collateralized Mortgage Backed Securities [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract] Due in one year or less Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis Due after one year through five years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Due after five years through ten years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis Due after ten years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis Amortized Cost Available-for-sale Debt Securities, Amortized Cost Basis Estimated Fair Value Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Due in one year or less Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Due after one year through five years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Due after five years through ten years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Due after ten years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value Estimated Fair Value Available-for-sale Securities, Debt Securities Amortized Cost Available-for-sale Securities, Amortized Cost Basis Estimated Fair Value Available-for-sale Securities Securities without contractual maturities, Amortized Cost Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis Securities without contractual maturities, Fair Value Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value Accounting Policies [Abstract] Nature of Operations and Summary of Significant Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Transfers and Servicing [Abstract] Constant prepayment rates (as a percent) Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Prepayment Speed Discount rate (as a percent) Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Discount Rate Loan servicing rights, valuation allowance Valuation Allowance for Impairment of Recognized Servicing Assets, Balance Fair Value Disclosures [Abstract] Fair Value Inputs, Assets, Quantitative Information [Table] Fair Value Inputs, Assets, Quantitative Information [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair value, measurements, nonrecurring Fair Value, Measurements, Nonrecurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Loan servicing rights Loan Servicing Rights [Member] Loan Servicing Rights [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Discounted cash flows Income Approach Valuation Technique [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Weighted Average Weighted Average [Member] Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Line Items] Other real estate owned Real Estate Acquired Through Foreclosure, Fair Value Disclosure Real Estate Acquired Through Foreclosure, Fair Value Disclosure Impaired loans Impaired Loans Receivable, Fair Value Disclosure Impaired Loans Receivable, Fair Value Disclosure Loan servicing rights Servicing Asset at Fair Value, Amount Property held for sale Assets Held-for-sale, Not Part of Disposal Group Constant prepayment rate (as a percent) Fair Value Inputs, Prepayment Rate Discount rate (as a percent) Fair Value Inputs, Discount Rate Derivative Instruments and Hedging Activities Disclosure [Abstract] Schedule of derivative positions, notional amounts and estimated fair values Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Summary of offsetting assets Offsetting Assets [Table Text Block] Summary of offsetting liabilities Offsetting Liabilities [Table Text Block] Schedule of derivative instruments, effect on other comprehensive income Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block] Receivables [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial real estate Commercial Real Estate Portfolio Segment [Member] Agriculture Agriculture Portfolio Segment [Member] Agriculture Portfolio Segment [Member] Commercial non-real estate Commercial Portfolio Segment [Member] Residential real estate Residential Portfolio Segment [Member] Consumer Consumer Portfolio Segment [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Outstanding Balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Recorded Investment Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Recorded Investment Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Recorded Investment Carrying Value Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Accrual Status [Axis] Accrual Status [Axis] Accrual Status [Axis] Accrual Status [Domain] Accrual Status [Domain] [Domain] for Accrual Status [Axis] Accruing Financing Receivables, Accruing [Member] Financing Receivables, Accruing [Member] Nonaccrual Financing Receivables, Nonaccrual [Member] Financing Receivables, Nonaccrual [Member] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Rate modification Contractual Interest Rate Reduction [Member] Term extension Extended Maturity [Member] Payment modification Payment Deferral [Member] Bankruptcy Bankruptcy Modification [Member] Bankruptcy Modification [Member] Other Other Modification [Member] Other Modification [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Recorded value of TDR balance Financing Receivable, Modifications, Recorded Investment Financing receivable, modifications, number of contracts Financing Receivable, Modifications, Number of Contracts Financing receivable, modifications, pre-modification recorded investment Financing Receivable, Modifications, Pre-Modification Recorded Investment Financing receivable, modifications, post-modification recorded investment Financing Receivable, Modifications, Post-Modification Recorded Investment Change in recorded investment due to principal paydown at time of modification, number of contracts Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Number of Contracts Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Number of Contracts Change in recorded investment due to principal paydown at time of modification, pre-modification Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Pre-Modification Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Pre-Modification Change in recorded investment due to principal paydown at time of modification, post-modification Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Post-Modification Financing Receivables, Impaired, Troubled Debt Restructuring, Principal Paydown, Post-Modification Change in recorded investment due to chargeoffs at time of modification, number of contracts Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Number of Contracts Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Number of Contracts Change in recorded investment due to chargeoffs at time of modification, pre-modification Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Pre-Modification Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Pre-Modification Change in recorded investment due to chargeoffs at time of modification, post-modification Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Post-Modification Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down, Post-Modification Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instruments Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swaps Interest Rate Swap [Member] Mortgage loan commitments Mortgage Loan Commitments [Member] Mortgage Loan Commitments [Member] Mortgage loan forward sale contracts Forward Contracts [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Financial institution counterparties FInancial Institution Counterparties [Member] FInancial Institution Counterparties [Member] Customer counterparties Customer Counterparties [Member] Customer Counterparties [Member] Derivative [Line Items] Derivative [Line Items] Notional Amount Derivative, Notional Amount Gross Asset Fair Value Derivative Asset, Fair Value, Gross Asset Gross Liability Fair Value Derivative Liability, Fair Value, Gross Liability Securities Available for Sale Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Federal Home Loan Banks [Abstract] FHLB Advances and Other Borrowings Federal Home Loan Bank, Advances [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted shares Restricted Stock [Member] Performance shares Performance Shares [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Common Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Shares, beginning of fiscal year (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Vested And Issued In Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Issued in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Canceled in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Canceled in Period Shares, end of period (in shares) Vested, but not issuable at end of period (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Vested, Not Issuable, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Not Issuable, Number Weighted-Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Shares, beginning of fiscal year (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Vested And Issued in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Issued in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Canceled (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Canceled, Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Canceled, Weighted Average Grant Date Fair Value Shares, end of period (in dollars per share) Vested, but not issuable at end of period (in dollars per share) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Vested, Not Issuable, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Not Issuable, Weighted Average Grant Date Fair Value Employee Benefit Plans Compensation and Employee Benefit Plans, Other than Share-based Compensation [Text Block] Defined Contribution Plan [Table] Defined Contribution Plan [Table] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Retirement Plan Name [Domain] Retirement Plan Name [Domain] Multiple employer 401(k) profit sharing plan Multiple Employer 401(k) Profit Sharing Plan [Member] Multiple Employer 401(k) Profit Sharing Plan [Member] Defined Contribution Plan Disclosure [Line Items] Defined Contribution Plan Disclosure [Line Items] Defined contribution plan, requisite service period Defined Contribution Plan, Requisite Service Period Defined Contribution Plan, Requisite Service Period Defined contribution plan, minimum age requirement Defined Contribution Plan, Minimum Age Requirement Defined Contribution Plan, Minimum Age Requirement Contributions by the Company Defined Contribution Plan, Employer Discretionary Contribution Amount Goodwill and Intangible Assets Disclosure [Abstract] Schedule of finite-lived intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of estimated amortization expense of intangible assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of fair value measurements of assets and liabilities Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of changes in Level 3 financial instruments Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Summary of mortgage loans held-for-sale, fair value measurement Fair Value Measurements, Nonrecurring [Table Text Block] Summary of valuation techniques and significant unobservable inputs used to measure Level 3 fair value measurements Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block] Schedule of fair values for balance sheet instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Trust Preferred Securities Subject to Mandatory Redemption Trust Preferred Securities Subject to Mandatory Redemption [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Junior Subordinated Debt Junior Subordinated Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Number of trusts Financial Instruments Subject to Mandatory Redemption, Number of Trusts Financial Instruments Subject to Mandatory Redemption, Number of Trusts Number of shares caused to be issued (in shares) Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Number of Shares Par value per shares issued (in dollars per share) Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Par Value Per Share Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Par Value Per Share Basis spread on variable rate (as a percent) Debt Instrument, Basis Spread on Variable Rate Maximum interest payment deferral period Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Maximum Interest Payment Deferral Period Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Maximum Interest Payment Deferral Period Total subordinated debentures and subordinated notes payable Long-term Debt Common shares held in other assets Common Stock Held in Assets Common Stock Held in Assets Summary of allowances for loan and lease losses Allowance for Credit Losses on Financing Receivables [Table Text Block] Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Federal Home Loan Bank Federal Home Loan Bank [Member] Federal Home Loan Bank [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Letter of Credit Letter of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] FRB Discount Window Loan Federal Reserve Board Discount Window Loan [Member] Federal Reserve Board Discount Window Loan [Member] Borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Unused capacity fee (as a percent) Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Interest rate at end of period (as a percent) Line of Credit Facility, Interest Rate at Period End Outstanding advances Long-term Line of Credit Loans pledged to the Federal Reserve Board Discount Window Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Other Arrangements Current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Loans pledged to the Federal Home Loan Bank Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Home Loan Bank Debt Loan Servicing Rights Transfers and Servicing of Financial Assets [Text Block] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Number of Loans Financing Receivable, Modifications, Subsequent Default, Number of Contracts Recorded Investment Financing Receivable, Modifications, Subsequent Default, Recorded Investment Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance, beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Principal paydown Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Balance, end of period Accounting Changes and Error Corrections [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2018-02 Accounting Standards Update 2018-02 [Member] Accounting Standards Update 2018-02 [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Tax Act - Stranded tax effects Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair value, measurements, recurring Fair Value, Measurements, Recurring [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] U.S. Treasury securities US Treasury Securities [Member] States and political subdivision securities US States and Political Subdivisions Debt Securities [Member] Other Other Debt Obligations [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total securities available for sale Derivatives-assets Derivative Asset Derivatives-liabilities Derivative Liability Fair value loans Loans Receivable And Written Loan Commitments, Fair Value Option Loans Receivable and Written Loan Commitments, Fair Value Option Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Impaired loans: Impaired Financing Receivable [Abstract] Impaired Financing Receivable [Abstract] With an allowance recorded: Impaired Financing Receivables, With An Allowance Recorded [Abstract] Impaired Financing Receivables, With An Allowance Recorded [Abstract] Recorded Investment Impaired Financing Receivable, with Related Allowance, Recorded Investment Unpaid Principal Balance Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance Related Allowance Impaired Financing Receivable, Related Allowance With no allowance recorded: Impaired Financing Receivables, With No Allowance Recorded [Abstract] Impaired Financing Receivables, With No Allowance Recorded [Abstract] Recorded Investment Impaired Financing Receivable, with No Related Allowance, Recorded Investment Unpaid Principal Balance Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Total Recorded Investment, Impaired Loans Impaired Financing Receivable, Recorded Investment Total Unpaid Principal Balance, Impaired Loans Impaired Financing Receivable, Unpaid Principal Balance Average recorded investment and interest income recognized on impaired loans: Impaired Financing Receivable, Average Recorded Investment And Interest Income [Abstract] Impaired Financing Receivable, Average Recorded Investment And Interest Income [Abstract] Average Recorded Investment Impaired Financing Receivable, with Related Allowance, Average Recorded Investment Interest Income Recognized While on Impaired Status Impaired Financing Receivable, Interest Income, Accrual Method Document And Entity Information [Abstract] Document Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Accounting for Certain Loans Acquired with Deteriorated Credit Quality Accounting for Certain Loans Acquired with Deteriorated Credit Quality [Text Block] Accounting for Certain Loans Acquired with Deteriorated Credit Quality [Text Block] Statement of Comprehensive Income [Abstract] Net income Net Income (Loss) Attributable to Parent Other comprehensive (loss) gain, net of tax: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Securities available for sale: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent [Abstract] Net unrealized holding (loss) gain arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification adjustment for net loss (gain) realized in net income Other Comprehensive Income (Loss), Reclassification Adjustment From AOCI For Sale Of Securities And Write-Down Of Securities, Before Tax Other Comprehensive Income (Loss), Reclassification Adjustment From AOCI For Sale Of Securities And Write-Down Of Securities, Before Tax Income tax benefit (expense) Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent Net change in unrealized (loss) gain on securities available for sale Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Defined benefit pension plan obligation: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent [Abstract] Net unrealized holding gain arising during the year Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Income tax (expense) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent Net change in defined benefit pension plan obligation Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Other comprehensive (loss) gain, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent States and political subdivision securities US Treasury and Government [Member] Other Other Security Investments [Member] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Less than 12 months, Estimated Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value 12 months or more, Estimated Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Estimated Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract] Less than 12 months, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 months or more, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Remaining in 2018 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2023 and thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Subordinated Debt Subordinated Debt [Member] GW Statutory Trust IV, variable rate of 2.85%, plus 3 month LIBOR GW Statutory Trust IV [Member] GW Statutory Trust IV [Member] GW Statutory Trust VI, variable rate of 1.48%, plus 3 month LIBOR GW Statutory Trust VI [Member] GW Statutory Trust VI [Member] SSB Trust II, variable rate of 1.85%, plus 3 month LIBOR SSB Trust II [Member] SSB Trust II [Member] HF Capital Trust III, variable rate of 3.35%, plus 3 month LIBOR HFB Trust III [Member] HFB Trust III [Member] HF Capital Trust IV, variable rate of 3.10%, plus 3 month LIBOR HFB Trust IV [Member] HFB Trust IV [Member] HF Capital Trust V, variable rate of 1.83%, plus 3 month LIBOR HFB Trust V [Member] HFB Trust V [Member] HF Capital Trust VI, variable rate of 1.65%, plus 3 month LIBOR HFB Trust VI [Member] HFB Trust VI [Member] Fixed to floating rate, 4.875% per annum Subordinated Notes Payable, Fixed To Floating Rate, Four Point Eight Five Percent [Member] Subordinated Notes Payable, Fixed To Floating Rate, Four Point Eight Five Percent [Member] Total subordinated debentures payable, amount outstanding Long-term Debt, Gross Total junior subordinated debentures payable, common shares held in other assets Less: fair value adjustment Long Term Debt, Fair Value Adjustment Long Term Debt, Fair Value Adjustment Less: unamortized debt issuance costs Unamortized Debt Issuance Expense Total Stated interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Schedule of loans receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of the Company's nonaccrual loans Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Schedule of the composition of the loan portfolio by internal risk rating Financing Receivable Credit Quality Indicators [Table Text Block] Schedule of past due loans Past Due Financing Receivables [Table Text Block] Schedule of impaired loans Impaired Financing Receivables [Table Text Block] Summary of troubled debt restructurings on accruing and nonaccrual loans Troubled Debt Restructurings on Financing Receivables [Table Text Block] Statement of Cash Flows [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Amortization of FDIC indemnification asset Amortization Of FDIC Indemnification Asset Amortization of FDIC Indemnification Asset Net loss on sale of securities and other assets Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Gain on redemption of subordinated debentures Gain (Loss) on Extinguishment of Debt Net gain on sale of loans Gain (Loss) on Sales of Loans, Net Provision for loan and lease losses Provision for Loan Losses Expensed Reversal of provision for loan servicing rights loss Provision For Loan Servicing Rights Loss Provision For Loan Servicing Rights Loss Stock-based compensation Share-based Compensation Originations of residential real estate loans held for sale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from sales of residential real estate loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Net deferred income taxes Deferred Income Taxes and Tax Credits Changes in: Increase (Decrease) in Operating Capital [Abstract] Accrued interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Other assets Increase (Decrease) in Other Operating Assets Accrued interest payable and other liabilities Increase (Decrease) in Accrued Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Purchase of securities available for sale Payments to Acquire Available-for-sale Securities Proceeds from sales of securities available for sale Proceeds from Sale of Available-for-sale Securities Proceeds from maturities of securities available for sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Net increase in loans Payments for (Proceeds from) Loans and Leases Payment of covered losses from FDIC indemnification claims Proceeds (Repayments) From Reimbursement Of FDIC Indemnification Claims Proceeds (Repayments) from Reimbursement of FDIC Indemnification Claims Purchase of premises and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sale of premises and equipment Proceeds from Sale of Property, Plant, and Equipment Proceeds from sale of repossessed property Proceeds from Sale of Other Assets, Investing Activities Purchase of FHLB stock Payments to Acquire Federal Home Loan Bank Stock Proceeds from redemption of FHLB stock Proceeds from Sale of Federal Home Loan Bank Stock Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Net increase in deposits Increase (Decrease) in Deposits Net decrease in securities sold under agreements to repurchase and other short-term borrowings Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net Proceeds from FHLB advances and other long-term borrowings Proceeds from Federal Home Loan Bank Borrowings Repayments on FHLB advances and other long-term borrowings Repayments of Federal Home Loan Bank Borrowings Redemption of subordinated debentures Repayments of Subordinated Debt Taxes paid related to net share settlement of equity awards Payments Related to Tax Withholding for Share-based Compensation Dividends paid Payments of Ordinary Dividends, Common Stock Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period Supplemental disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Cash payments for interest Interest Paid Cash payments for income taxes Income Taxes Paid Supplemental disclosure of noncash investing and financing activities Noncash Investing and Financing Items [Abstract] Loans transferred to repossessed properties Transfer Of Loans To Repossessed Assets Transfer of Loans to Repossessed Assets Summary of restricted share and performance-based stock award activity Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Income Tax Contingency [Table] Income Tax Contingency [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Internal Revenue Service (IRS) Internal Revenue Service (IRS) [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Great Western Bank Great Western Bank [Member] Great Western Bank [Member] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Federal tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Income taxes receivable Income Taxes Receivable Provision for income taxes Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Increase in provision for income taxes Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Effective income tax percentage Effective Income Tax Rate Reconciliation, Percent Effective income tax percentage, excluding nonrecurring deferred tax adjustment related to federal tax reform Effective Income Tax Rate Reconciliation, Percent, Excluding Nonrecurring Deferred Tax Adjustment Related To Tax Reform Effective Income Tax Rate Reconciliation, Percent, Excluding Nonrecurring Deferred Tax Adjustment Related To Tax Reform Earnings Per Share [Abstract] Weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Dilutive effect of stock based compensation (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average common shares outstanding for diluted earnings per share calculation (in shares) Weighted Average Number of Shares Outstanding, Diluted Basic earnings per share (in dollars per share) Earnings Per Share, Basic Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Mortgage-backed securities Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Investment Type [Axis] Investment Type [Axis] Investment [Domain] Investments [Domain] Government National Mortgage Association Government National Mortgage Association Certificates and Obligations (GNMA) [Member] Federal Home Loan Mortgage Corporation Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Federal National Mortgage Association Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Small Business Assistance Program Mortgage-Backed Securities, Small Business Assistance Program [Member] Mortgage-backed Securities, Small Business Assistance Program [Member] Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] Amortized Cost Gross Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock awards Stock Compensation Plan [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Summary of the fair value option Fair Value, Option, Quantitative Disclosures [Table Text Block] Amortization of core deposits and other intangibles Amortization of Intangible Assets Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Other repossessed property Loans held for sale, at lower of cost or fair value Loans Held-for-sale, Fair Value Disclosure Property held for sale Assets Held-for-sale, Long Lived, Fair Value Disclosure Statement of Financial Position [Abstract] Assets Assets [Abstract] Loans covered by FDIC loss share agreements Loans and Leases Receivable, Net Reported Amount, Covered Loans and written loan commitments at fair value under the fair value option Loan held for sale Loans Receivable Held-for-sale, Amount Property covered under FDIC loss share agreements Other Real Estate, Covered Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Stockholders’ equity Stockholders' Equity Attributable to Parent [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Eligible Item or Group for Fair Value Option [Axis] Financial Instrument [Axis] Fair Value, Option, Eligible Item or Group [Domain] Financial Instruments [Domain] Long-term loans Loans Receivable [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Noninterest Income Noninterest Income [Member] Noninterest Income Change in fair value of loans Fair Value, Option, Changes in Fair Value, Gain (Loss) Nonaccrual loans, excluding loans covered under FDIC loss-sharing arrangements Financing Receivable, Recorded Investment, Nonaccrual Status Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Balance at beginning of period Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Reclassification from nonaccretable difference Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Balance at end of period Earnings per Share Earnings Per Share [Text Block] Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities [Domain] Loans Insured or Guaranteed by Government Authorities [Domain] Loans Guaranteed by US Government Authorities Loans Insured or Guaranteed by US Government Authorities [Member] Unamortized discount on acquired loans Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Loans in process Loans and Leases Receivable, Loans in Process Loans guaranteed by U.S. Government Agencies Financing Receivable, Net Principal balances of residential real estate loans sold Mortgage Loans on Real Estate, Cost of Mortgages Sold Loans greater than 90 days past due and still accruing interest Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Valuation adjustments made to repossessed properties Real Estate Owned, Valuation Allowance, Period Increase (Decrease) Specific reserves included in the allowance for loan losses for TDRs Allowance for Credit Losses, Change in Method of Calculating Impairment Troubled debt restructuring, commitments to lend additional funds Financing Receivable, Modifications, Unused Commitments to Extend Credit Financing Receivable, Modifications, Unused Commitments to Extend Credit Transfers out of troubled debt restructuring status Financing Receivable, Transfers out of Troubled Debt Restructuring, Amount Financing Receivable, Transfers out of Troubled Debt Restructuring, Amount Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract] Schedule of repurchases agreements Schedule of Repurchase Agreements [Table Text Block] Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Past Due Nonperforming Financial Instruments [Member] Current Performing Financial Instruments [Member] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] 30-59 Days Past Due Financing Receivables, 30 to 59 Days Past Due [Member] 60-89 Days Past Due Financing Receivables, 60 to 89 Days Past Due [Member] 90 Days or Greater Past Due Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Other Unallocated Financing Receivables [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing receivables, net of unamortized discount on acquired loans Loans And Leases Receivable, Net Of Unamortized Discount On Acquired Loans Loans and Leases Receivable, Net of Unamortized Discount on Acquired Loans Loans covered by FDIC loss sharing agreements Total Loans and Leases Receivable, Net Reported Amount, Covered and Not Covered Schedule of correction of prior period balances Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Receivables Acquired with Deteriorated Credit Quality [Axis] Receivables Acquired with Deteriorated Credit Quality [Axis] Receivables Acquired with Deteriorated Credit Quality [Domain] Receivables Acquired with Deteriorated Credit Quality [Domain] Acquired receivables subject to ASC 310-30 Receivables Acquired with Deteriorated Credit Quality [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Allowance for loan and lease losses Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Total allowance Loans and Leases Receivable, Allowance Financing Receivables Financing Receivable, Net [Abstract] Individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Loans Outstanding Schedule of basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Cash and due from banks Cash and Due from Banks Interest-bearing bank deposits Interest-bearing Deposits in Banks and Other Financial Institutions Cash and cash equivalents Securities available for sale Loans, net of unearned discounts and deferred fees, including $50,727 and $57,537 of loans covered by a FDIC loss share agreement at March 31, 2018 and September 30, 2017, respectively, and $920,965 and $1,016,576 of loans at fair value under the fair value option at March 31, 2018 and September 30, 2017, respectively, and $2,429 and $7,456 of loans held for sale at March 31, 2018 and September 30, 2017, respectively Loans and Leases Receivable, Net of Deferred Income Allowance for loan and lease losses Net loans Loans and Leases Receivable, Net Amount Premises and equipment, including $1,109 and $5,147 of property held for sale at March 31, 2018 and September 30, 2017, respectively Property, Plant and Equipment, Net Accrued interest receivable Interest Receivable Other repossessed property, including $86 and $0 of property covered by FDIC loss share agreements at March 31, 2018 and September 30, 2017, respectively Repossessed Assets Goodwill Goodwill Cash surrender value of life insurance policies Cash Surrender Value of Life Insurance Net deferred tax assets Deferred Tax Assets, Net Other assets Other Assets Total assets Assets Deposits Deposits, Interest-bearing and Noninterest-bearing, Alternative [Abstract] Noninterest-bearing Noninterest-bearing Deposit Liabilities Interest-bearing Interest-bearing Deposit Liabilities Total deposits Deposits Securities sold under agreements to repurchase Securities Sold under Agreements to Repurchase FHLB advances and other borrowings Advances From Federal Home Loan Banks And Other Borrowings Advances from Federal Home Loan Banks and Other Borrowings Subordinated debentures and subordinated notes payable Subordinated Debt Accrued expenses and other liabilities Accrued Liabilities and Other Liabilities Total liabilities Liabilities Common stock, $0.01 par value, authorized 500,000,000 shares; 58,896,189 shares issued and outstanding at March 31, 2018 and 58,834,066 shares issued and outstanding at September 30, 2017 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders' equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders' equity Liabilities and Equity Loans Loans, Notes, Trade and Other Receivables, Excluding Allowance for Credit Losses [Text Block] Schedule of Income Tax Expense (Benefit) Components Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Banking and Thrift [Abstract] Summary of FDIC indemnification asset activity FDIC Indemnification Asset Roll Forward [Table Text Block] Schedule of loan servicing rights and valuation allowance activity Servicing Asset at Amortized Cost [Table Text Block] Derivative assets, gross amount Derivative assets, fair value offset amount Derivative Asset, Fair Value, Gross Liability Derivative assets, cash collateral Derivative, Collateral, Obligation to Return Cash Derivative financial assets, net amount presented in Consolidated Balance Sheets Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative liabilities, gross amount Derivative liabilities, fair value offset amount Derivative Liability, Fair Value, Gross Asset Derivative liabilities, cash collateral Derivative, Collateral, Right to Reclaim Cash Derivative financial liabilities, net amount presented in Consolidated Balance Sheets Derivative Liability, Fair Value, Amount Not Offset Against Collateral Security collateral Derivative, Collateral, Right to Reclaim Securities Collateral held for initial margin Derivative, Collateral, Held For Initial Margin Derivative, Collateral, Held For Initial Margin Noninterest income Amount of Gain (Loss) Recognized in Statements of Income Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Comprehensive Income Comprehensive Income [Member] Common Stock Par Value Common Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance Net income Other comprehensive (loss), net of tax Stock-based compensation, net of tax Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Reclassification due to adoption of ASU 2018-02 Common stock cash dividends Dividends, Common Stock, Cash Ending balance Cash dividends paid on common stock (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Schedule of Assets Sold under Agreements to Repurchase [Table] Schedule of Assets Sold under Agreements to Repurchase [Table] Securities or Other Assets Sold under Agreements to Repurchase, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Assets Sold under Agreements to Repurchase, Maturity Period [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Overnight and Continuous Maturity Overnight [Member] Up to 30 Days Maturity Less than 30 Days [Member] 30-90 Days Maturity 30 to 90 Days [Member] Greater than 90 Days Maturity Greater than 90 Days [Member] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Assets Sold under Agreements to Repurchase, Type [Domain] Assets Sold under Agreements to Repurchase, Type [Domain] Municipal securities Assets Sold under Agreements to Repurchase [Line Items] Assets Sold under Agreements to Repurchase [Line Items] Total repurchase agreements FHLB Advances and Related Party Notes Payable FHLB Advances And Other Borrowings [Member] FHLB Advances and Related Party Notes Payable [Member] Remaining in 2018 Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three 2021 Long-term Debt, Maturities, Repayments of Principal in Year Four 2022 Long-term Debt, Maturities, Repayments of Principal in Year Five 2023 and thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Subsequent Events Subsequent Events, Policy [Policy Text Block] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of troubled debt restructurings Schedule of Deteriorated Loans Transferred in [Table Text Block] Schedule of Deteriorated Loans Transferred in [Table Text Block] Schedule of impaired loans Income Statement [Abstract] Interest income Interest and Fee Income, Loans and Leases [Abstract] Loans Interest and Fee Income, Loans and Leases Investment securities Interest Income, Operating Federal funds sold and other Interest Income, Federal Funds Sold and Securities Purchased under Agreements to Resell Total interest income Interest and Dividend Income, Operating Interest expense Interest Expense [Abstract] Deposits Interest Expense, Deposits FHLB advances and other borrowings Interest Expense, Federal Home Loan Bank and Federal Reserve Bank Advances, Short-term Subordinated debentures and subordinated notes payable Interest Expense, Subordinated Notes and Debentures Total interest expense Interest Expense Net interest income Interest Income (Expense), Net Provision for loan and lease losses Provision for Loan, Lease, and Other Losses Net interest income after provision for loan and lease losses Interest Income (Expense), after Provision for Loan Loss Noninterest income Noninterest Income [Abstract] Service charges and other fees Fees and Commissions Wealth management fees Investment Banking Revenue Mortgage banking income, net Fees and Commissions, Mortgage Banking Net (loss) gain on sale of securities Gain (Loss) on Sale of Securities, Net Net (decrease) in fair value of loans at fair value Net realized and unrealized gain on derivatives Derivatives, Net Realized And Unrealized Gain (Loss) Derivatives, Net Realized and Unrealized Gain (Loss) Other Noninterest Income, Other Total noninterest income Noninterest Income Noninterest expense Noninterest Expense [Abstract] Salaries and employee benefits Labor and Related Expense Data processing and communication Information Technology and Data Processing Occupancy and equipment Occupancy, Net Professional fees Professional Fees Advertising Advertising Expense Net loss recognized on repossessed property and other related expenses Net (Gain) Loss From Sale Of Repossessed Property And Other Assets Net (gain) loss from sale of repossessed property and other assets Amortization of core deposits and other intangibles Amortization of Deferred Charges Acquisition expenses Business Combination, Acquisition Related Costs Other Other Noninterest Expense Total noninterest expense Noninterest Expense Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for income taxes Income Tax Expense (Benefit) Net income Basic earnings per common share Earnings Per Share, Basic [Abstract] Weighted average shares outstanding (in shares) Earnings per share (in dollars per share) Diluted earnings per common share Earnings Per Share, Diluted [Abstract] Weighted average shares outstanding (in shares) Diluted earnings per share (in dollars per share) Dividends per share Dividends Per Share [Abstract] Dividends Per Share [Abstract] Dividends paid Dividends per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Schedule of FHLB advances and other borrowings Schedule of Debt [Table Text Block] Schedule of FHLB advances and other borrowings by maturity date Summary of Maturities of Federal Home Loan Bank Advances [Table Text Block] Summary of Maturities of Federal Home Loan Bank Advances Income tax expense computed at the statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Tax exempt interest income Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Impact of enacted federal income tax rate reduction Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Income tax expense Dividends Payable [Table] Dividends Payable [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent event Subsequent Event [Member] Dividends Payable [Line Items] Dividends Payable [Line Items] Common stock dividends declared (in dollars per share) Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Immaterial Classification Error Related To Credit Card Interchange Income Immaterial Classification Error Related To Credit Card Interchange Income [Member] Immaterial Classification Error Related To Credit Card Interchange Income [Member] As originally reported Scenario, Previously Reported [Member] Adjustments Restatement Adjustment [Member] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Interest income - loans Noninterest income - service charges and other fees Total financing receivables, gross Loans and Leases Receivable, Gross Less: Unamortized discount on acquired loans Loans and Leases Receivable, Deferred Income, Unamortized Discounts or Premiums on Acquired Loans Loans and Leases Receivable, Deferred Income, Unamortized Discounts or Premiums on Acquired Loans Unearned net deferred fees and costs and loans in process Loans and Leases Receivable, Loans in Process and Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Loans and Leases Receivable, Loans in Process and Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Net loans Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Core Deposit Intangible Core Deposits [Member] Brand Intangible Marketing-Related Intangible Assets [Member] Other Intangible Other Intangible Assets [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross carrying amount Finite-Lived Intangible Assets, Gross Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Available-for-sale securities, gross realized gains Available-for-sale Securities, Gross Realized Gains Available-for-sale securities, gross realized losses Available-for-sale Securities, Gross Realized Losses Other than temporary impairment losses recognized in earnings Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Securities pledged as collateral Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment Percentage of investment portfolio in continuous loss position (as a percent) Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Percentage of Investment Portfolio Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Percentage of Investment Portfolio Number of securities in an unrealized loss position (securities) Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions (Impairment) improvement of ASC 310-30 loans Class of Financing Receivable [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable, Type [Domain] Loans and Leases with Allowance Loans And Leases With Allowance For Doubtful Accounts [Member] Loans And Leases With Allowance For Doubtful Accounts [Member] Unfunded loan commitment Unfunded Loan Commitment [Member] Allowance for loan leases Net reversal of provision Allowance for Loan and Lease Loss, Recovery of Bad Debts Reserve for unfunded loan commitments Loans and Leases Receivable, Reserve for Future Loan Commitments Loans and Leases Receivable, Reserve for Future Loan Commitments Share-based payment award, award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based compensation expense Allocated Share-based Compensation Expense Tax benefit from compensation expense Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Share-based compensation, compensation cost not yet recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Share-based compensation, compensation cost not yet recognized, recognition period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Fair value of vested stock awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value FDIC Indemnification Asset [Roll Forward] FDIC Indemnification Asset [Roll Forward] Balance at beginning of period FDIC Indemnification Asset Amortization FDIC Indemnification Asset, Accretion of Discount Changes in expected reimbursements from FDIC for changes in expected credit losses FDIC Indemnification Asset, Increase (Decrease) in Expected Reimbursements from FDIC FDIC Indemnification Asset, Increase (Decrease) in Expected Reimbursements from FDIC Changes in reimbursable expenses FDIC Indemnification Asset, Increase (Decrease) in Reimbursable Expenses FDIC Indemnification Asset, Increase (Decrease) in Reimbursable Expenses Reimbursements of covered losses to the FDIC FDIC Indemnification Asset, Cash Payments Received Balance at end of period Summary of subordinated debentures and subordinated notes payable Schedule of Long-term Debt Instruments [Table Text Block] Deferred tax assets: Deferred Tax Assets, Gross [Abstract] Allowance for loan losses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Provision for Loan Losses Compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Securities available for sale Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross Other real estate owned Deferred Tax Assets, Other Real Estate Owned Deferred Tax Assets, Other Real Estate Owned Core deposit intangible and other fair value adjustments Deferred Tax Assets, Goodwill and Intangible Assets Excess tax basis of FDIC indemnification asset and clawback liability Deferred Tax Assets, Excess Tax Basis of FDIC Indemnification Asset and Clawback Liability Deferred Tax Assets, Excess Tax Basis of FDIC Indemnification Asset and Clawback Liability Excess tax basis of loans acquired over carrying value Deferred Tax Assets, Excess Tax Basis of Loans Acquired Over Carrying Value Deferred Tax Assets, Excess Tax Basis of Loans Acquired Over Carrying Value Other reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Goodwill and other intangibles Deferred Tax Liabilities, Goodwill and Intangible Assets Premises and equipment Deferred Tax Liabilities, Property, Plant and Equipment Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax assets Allowance for Loan and Lease Losses Allowance for Credit Losses [Text Block] Derivative, remaining maturity (or less) Financial Instruments, Fair Value Approximates Carrying Value Condition, Maximum Remaining Maturity Financial Instruments, Fair Value Approximates Carrying Value Condition, Maximum Remaining Maturity Loan servicing rights Servicing Asset at Amortized Cost, Balance [Roll Forward] Beginning of period Servicing Asset At Amortized Cost, Gross Servicing Asset At Amortized Cost, Gross Additions Servicing Asset at Amortized Cost, Additions Amortization Servicing Asset at Amortized Cost, Amortization End of period Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward] Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward] Beginning of period (Additions) / reductions Valuation Allowance for Impairment of Recognized Servicing Assets, Period Increase (Decrease) End of period Loan servicing rights, net Servicing Asset at Amortized Cost Servicing fees received Bank Servicing Fees Balance of loans serviced at: Loans Serviced Roll Forward [Roll Forward] Loans Serviced Roll Forward [Roll Forward] Beginning of period Loans Serviced Loans Serviced End of period Securities Sold Under Agreements to Repurchase Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block] Securities sold under agreements to repurchase Securities Sold under Agreements to Repurchase, Gross Securities sold under agreements to repurchase, fair value of collateral Securities Sold under Agreements to Repurchase, Fair Value of Collateral Securities sold under agreements to repurchase, collateral, percentage of borrowed funds (as a percent) Securities Sold under Agreements to Repurchase, Collateral, Percentage of Total Borrowed Funds Securities Sold under Agreements to Repurchase, Collateral, Percentage of Total Borrowed Funds Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Loans, net excluding fair valued loans and loans held for sale Accrued interest receivable Receivables, Fair Value Disclosure Cash surrender value of life insurance policies Cash Surrender Value, Fair Value Disclosure FHLB stock Investment in Federal Home Loan Bank Stock, Fair Value Disclosure Liabilities Liabilities [Abstract] Deposits Deposits, Fair Value Disclosure FHLB advances and other borrowings Federal Home Loan Bank Borrowings, Fair Value Disclosure Securities sold under repurchase agreements Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure Accrued interest payable Accounts Payable, Fair Value Disclosure Subordinated debentures and subordinated notes payable Subordinated Debt Obligations, Fair Value Disclosure FDIC Indemnification Asset FDIC Indemnification Asset [Text Block] FDIC Indemnification Asset [Text Block] Face amount of debt issued Debt Instrument, Face Amount Redemption price, percentage of principal (as a percent) Debt Instrument, Redemption Price, Percentage Unamortized debt issuance costs Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Notes payable to banks Notes Payable to Banks [Member] Federal Home Loan Bank fed funds advance Federal Home Loan Bank Advances [Member] Interest rate (as a percent) Federal Home Loan Bank, Advances, Interest Rate Federal Home Loan Bank (FHLB) notes payable and fed funds advance Advances from Federal Home Loan Banks Total Advances From Federal Home Loan Banks And Other Borrowings, Before Fair Value Adjustment Advances From Federal Home Loan Banks And Other Borrowings, Before Fair Value Adjustment Fair value adjustment Advances From Federal Home Loan Banks And Other Borrowings, Fair Value Adjustment Advances From Federal Home Loan Banks And Other Borrowings, Fair Value Adjustment Total FHLB advances and other borrowings Eligible item for the fair value option Fair Value, Option, Loans Held as Assets, Aggregate Difference Total unpaid principal balance of long-term loans Fair Value, Option, Aggregate Unpaid Principal Balance Fair Value, Option, Aggregate Unpaid Principal Balance Loans greater than 90 days past due or in nonaccrual status Fair Value, Option, Loans Held as Assets, Aggregate Amount 90 Days or More Past Due or in Nonaccrual Status Fair Value, Option, Loans Held as Assets, Aggregate Amount 90 Days or More Past Due or in Nonaccrual Status Unpaid principal balance greater than 90 days past due or in nonaccrual status Fair Value, Option, Loans Held As Assets, Unpaid Principal Balance, 90 Days Or More Past Due Or In Nonaccrual Status Fair Value, Option, Loans Held As Assets, Unpaid Principal Balance, 90 Days Or More Past Due Or In Nonaccrual Status Eligible item for the fair value option Eligible Item or Group For Fair Value Option Eligible Item or Group For Fair Value Option The Fair Value Option For Certain Loans Fair Value, Option [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Currently paid or payable Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Current income tax expense (benefit) Current Income Tax Expense (Benefit) Deferred tax expense