Income Tax Disclosure [Abstract] Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Receivables [Abstract] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Class of Financing Receivable [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable, Type [Domain] Construction Real Estate Loans Construction Loans [Member] 1-4 Family Residential Real Estate Loans Residential Real Estate [Member] Commercial Real Estate Loans Commercial Real Estate Portfolio Segment [Member] Commercial Loans Commercial Loan [Member] Municipal Loans Municipal Loans [Member] Class of financing receivables related to state, city or local governments or the agencies operated by state, city or local governments. Loans to Individuals Consumer Loan [Member] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Unpaid Contractual Principal Balance Impaired Financing Receivable, Unpaid Principal Balance Recorded Investment Impaired Financing Receivable, with Related Allowance, Recorded Investment Related Allowance for Loan Losses Impaired Financing Receivable, Related Allowance PCI loans that experienced deterioration in credit quality subsequent to acquisition Purchase Credit Impaired Loans, with Deterioration in Credit Quality After Acquisition Purchase Credit Impaired Loans, with deterioration in credit qualify after acquisition Debt Disclosure [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swap derivatives Interest Rate Swap [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Three-Month London Interbank Offered Rate (LIBOR) Three-Month London Interbank Offered Rate (LIBOR) [Member] Three-Month London Interbank Offered Rate (LIBOR) [Member] One-Month London Interbank Offered Rate (LIBOR) One-Month London Interbank Offered Rate (LIBOR) [Member] One-Month London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Variable Rate Advance Agreements Variable Rate Advance Agreements [Member] Variable Rate Advance Agreements [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Frost Bank Frost Bank [Member] Frost Bank [Member] TIB - The Independent Bankers Bank TIB - The Independent Bankers Bank [Member] TIB - The Independent Bankers Bank [Member] Comerica Bank Comerica Bank [Member] Comerica Bank [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] FHLB borrowings interest rates Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Interest Rate at Period End FHLB borrowings maturities Federal Home Loan Bank, Advances, Maturities Summary, Maturity Range Represents the range of years until maturity from lowest to highest that are applicable to Federal Home Loan Bank outstanding as of the balance sheet date. FHLB borrowings with variable interest rate, face amount Debt Instrument, Face Amount Debt Instrument, Number Of Variable Rate Advance Agreements Debt Instrument, Number Of Variable Rate Advance Agreements Debt Instrument, Number Of Variable Rate Advance Agreements FHLB borrowings, description of variable rate basis Debt Instrument, Description of Variable Rate Basis FHLB borrowings, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Derivative, fixed interest rate Derivative, Fixed Interest Rate Derivative, term of contract Derivative, Term of Contract Derivative, instruments terminated Derivative, instruments terminated Derivative, instruments terminated Derivative, terminated, notional amount Derivative, terminated, notional amount Derivative, terminated, notional amount Number of credit lines maintained by the Company Line of Credit Facility, Number of Credit Lines Maintained by the Company Line of Credit Facility, Number of Credit Lines Maintained by the Company Line of credit, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Federal funds purchased Federal Funds Purchased Line of credit, capacity available for issuance of letters of credit Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases Number of outstanding letters of credit Number of outstanding letters of credit Number of Outstanding Letters of Credit Letters of credit outstanding, amount Letters of Credit Outstanding, Amount FHLB borrowings, additional funding available Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds Letters of Credit, FHLB, as collateral Letters of Credit, FHLB, as Collateral The amount of letters of credit outstanding at year end from the Federal Home Loan Bank as collateral for its public fund deposits. Securities sold under agreements to repurchase Securities Sold under Agreements to Repurchase Maturity of repurchase agreements Repurchase Agreement Counterparty, Maturity of Agreements Repurchase Agreement Counterparty, Maturity of Agreements Income Statement [Abstract] Statement [Table] Statement [Table] Restatement [Axis] Restatement [Axis] Restatement [Domain] Restatement [Domain] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Deposit services Deposit Account [Member] Statement [Line Items] Statement [Line Items] Interest income Interest and Dividend Income, Operating [Abstract] Loans Interest and Fee Income, Loans and Leases Investment securities – taxable Interest Income, Securities, Operating, Taxable Investment securities – tax-exempt Interest Income, Securities, Operating, Tax Exempt Mortgage-backed securities Interest Income, Securities, Mortgage Backed FHLB stock and equity investments Other Interest and Dividend Income Other interest earning assets Interest Income, Other Total interest income Interest and Dividend Income, Operating Interest expense Interest Expense [Abstract] Deposits Interest Expense, Deposits FHLB borrowings Interest expense, Federal Home Loan Bank Advances Interest expense incurred during the reporting period on borrowings not defined elsewhere in the taxonomy. Includes interest expense incurred on both the short-term and long-term borrowings (advances) with the Federal Home Loan Bank. Subordinated notes Interest Expense, Subordinated Notes and Debentures Trust preferred subordinated debentures Interest Expense, Junior Subordinated Debentures Other borrowings Interest Expense, Other Total interest expense Interest Expense Net interest income Interest Income (Expense), Net Provision for loan losses Provision for Loan and Lease Losses Net interest income after provision for loan losses Interest Income (Expense), after Provision for Loan Loss Noninterest income Noninterest Income [Abstract] Deposit services Fee And Commissions Depositor Account Includes amounts charged depositors for: (1) maintenance of their accounts (maintenance charges); (2) failure to maintain specified minimum balances on account; (3) exceeding the number of checks or transactions allowed to be processed in a given period; (4) checks drawn on no minimum balance deposit accounts; (5) withdrawals from nontransaction deposit accounts; (6) closing savings accounts before a specified minimum period of time has elapsed; (7) accounts which have remained inactive for extended periods of time or which have become dormant; (8) use of automated teller machines or remote service units; (9) checks drawn against insufficient funds that the bank assesses regardless of whether it decides to pay, return or hold the check; (10) issuing stop payment orders; (11) certifying checks; and (12) accumulating or disbursing funds deposited in IRAs or Keogh Plan accounts when not handled by the bank's trust department. This item does not include penalties assessed on the early withdrawal of time deposits. Net (loss) gain on sale of securities available for sale Debt and Equity Securities, Gain (Loss) Gain on sale of loans Gain (Loss) on Sales of Loans, Net Trust income Fees And Commissions Fiduciary And Trust Activity Income from services rendered by trust departments or by any consolidated subsidiaries acting in a fiduciary capacity, including fees earned for (1) acting as an agent for fiduciary placement and loans and (2) custody or investment advisory services when such fees are not separately billed to the customer. This item excludes commissions and fees received for the accumulation or disbursement of funds deposited to Individual Retirement or Keogh plan accounts when such are not handled by the reporting entity's trust department. Bank owned life insurance income Bank Owned Life Insurance Income Brokerage services Brokerage Commissions Revenue Other Noninterest Income, Other Operating Income Total noninterest income Noninterest Income Noninterest expense Noninterest Expense [Abstract] Salaries and employee benefits Labor and Related Expense Occupancy expense Occupancy, Net Acquisition expense Business Combination, Acquisition Related Costs Advertising, travel & entertainment Marketing and Advertising Expense ATM and debit card expense ATM And Debit Card Expense Expenses associated with the cost of offering debit cards and ATM cards. Professional fees Professional Fees Software and data processing expense Information Technology and Data Processing Telephone and communications Communication FDIC insurance Federal Deposit Insurance Corporation Premium Expense Amortization expense on intangibles Amortization of Intangible Assets Other Other Noninterest Expense Total noninterest expense Noninterest Expense Income before income tax expense Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Earnings per common share - basic (in dollars per share) Earnings Per Share, Basic Earnings per common share - diluted (in dollars per share) Earnings Per Share, Diluted Dividends paid per common share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Fair Value Disclosures [Abstract] 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] Estimated Fair Value Estimate of Fair Value Measurement [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financial Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investment Securities: Investments, Fair Value Disclosure [Abstract] Held to maturity, at carrying value Investment Securities Held-to-maturity Securities, Fair Value Disclosure Investment Securities Held-to-maturity Securities, Fair Value Disclosure Mortgage-backed Securities: Mortgage Backed And Related Securities [Abstract] Mortgage Backed And Related Securities [Abstract] Held to maturity, at carrying value Mortgage-backed Securities Held-to-maturity, Fair Value Disclosure FHLB stock, at cost Investment in Federal Home Loan Bank Stock, Fair Value Disclosure Equity investments Investments, Fair Value Disclosure Loans, net of allowance for loan losses Loans Receivable, Fair Value Disclosure Loans held for sale Loans Held-for-sale, Fair Value Disclosure Financial Liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Deposits Deposits, Fair Value Disclosure Federal funds purchased and repurchase agreements Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure FHLB borrowings Federal Home Loan Bank Borrowings, Fair Value Disclosure Subordinated notes, net of unamortized debt issuance costs Subordinated Debt Obligations, Fair Value Disclosure Trust preferred subordinated debentures, net of unamortized debt issuance costs Debt Instrument, Fair Value Disclosure Defined Contribution Plan [Abstract] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Weighted Average Maturity And Interest Rates On Risk Management Interest Rate Swaps [Table Text Block] Weighted Average Maturity And Interest Rates On Risk Management Interest Rate Swaps [Table Text Block] [Table Text Block] for Weighted average remaining maturity of the notional amount of risk management interest rate swaps and weighted average interest rates. Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Schedule of Financing Receivables Past Due [Table] 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] Greater than 90 Days Past Due Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Total Past Due Financing Receivable, Recorded Investment, Past Due Current Financing Receivable, Recorded Investment, Current Total ending loan balance Loans and Leases Receivable, Gross Debt [Table] Debt [Table] Debt [Table] Federal funds purchased and repurchase agreements: Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] FHLB borrowings: Federal Home Loan Bank Advances [Member] Subordinated notes, net of unamortized debt issuance costs: Subordinated Debt [Member] Trust preferred subordinated debentures, net of unamortized debt issuance costs: Junior Subordinated Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Federal funds purchased and repurchase agreements Federal Funds Purchased and Securities Sold under Agreements to Repurchase FHLB borrowings Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances Subordinated notes, net of unamortized debt issuance costs: Subordinated Debt Trust preferred subordinated debentures, net of unamortized debt issuance costs Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Average amount outstanding during the period Borrowings, Average Amount Outstanding Borrowings, Average Amount Outstanding Maximum amount outstanding during the period Borrowings, Maximum Month-end Outstanding Amount Borrowings, Maximum Month-end Outstanding Amount Weighted average interest rate during the period Debt, Weighted Average Interest Rate Interest rate at end of the period Debt Instrument, Interest Rate, Effective Percentage Commitments and Contingencies Disclosure [Abstract] Schedule of Fair Value, Off-balance Sheet Risks [Table] Schedule of Fair Value, Off-balance Sheet Risks [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Commitments to extend credit Commitments to Extend Credit [Member] Standby letters of credit Standby Letters of Credit [Member] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Financial instruments with off-balance-sheet risk, at fair value Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale and Held to Maturity Securities [Table] Schedule of Available-for-sale and Held to Maturity Securities [Table] Schedule of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities and of all investments in certain debt and equity securities for which the entity has the positive intent and ability to hold until maturity. US Government Agency Debentures US Government-sponsored Enterprises Debt Securities [Member] State and Political Subdivisions US States and Political Subdivisions Debt Securities [Member] Other Stocks and Bonds Other Stocks and Bonds [Member] This category includes information about ownership interests or the right to acquire ownership interests in corporations and other legal entities which ownership interest is represented by shares of common or preferred stock (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, stock rights, or stock warrants, and debt instrument issued by corporations, governments and governmental agencies, municipalities, and other institutions. Other Equity Securities Equity Securities [Member] Residential Residential Mortgage Backed Securities [Member] Commercial Commercial Mortgage Backed Securities [Member] Schedule of Available-for-sale and Held-to-maturity Securities [Line Items] Schedule of Available-for-sale and Held-to-maturity Securities [Line Items] Schedule of Available-for-sale and Held-to-maturity Securities [Line Items] Available-for-sale, Unrealized Loss Position [Abstract] Debt Securities, Available-for-sale, Unrealized Loss Position [Abstract] Less than 12 Months, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Less than 12 months, fair value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value More than 12 Months, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer More than 12 months, fair value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Total fair value Debt Securities, Available-for-sale, Unrealized Loss Position Total fair value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] Less than 12 Months, unrealized loss Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Less than 12 Months, unrealized loss Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss More than 12 Months, unrealized Loss Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss More than 12 months, unrealized loss Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total unrealized loss Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Total unrealized loss Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] Less than 12 months, fair value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value More than 12 Months, fair value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Total fair value Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Losses [Abstract] Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] Less than 12 months, unrealized loss Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss More than 12 months, unrealized loss Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total unrealized loss Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss Securities: Debt Securities, Available-for-sale and Held-to-maturity [Abstract] Unsettled trades to purchase securities Unsettled Trades to Purchase Securities Liability Amount of securities purchased that were not settled by the end of the period. The amount recorded is the purchase price including any accrued interest. This asset is collected upon delivery of the securities. Unsettled trades to sell securities Unsettled Trades to Sell Securities Amount of securities sold that were not settled by the end of the period. The amount recorded is the selling price including any accrued interest. This asset is collected upon delivery of the securities. Deposits: Deposits [Abstract] Unsettled Issuances of Brokered CDs Unsettled Issuances of Brokered CDs Amount of brokered CDs sold that were not settled by the end of the period. The amount recorded is the selling price including any accrued interest. Amortized cost and estimated fair value of investment and mortgage-backed securities Unrealized Gain (Loss) on Investments [Table Text Block] Unrealized loss on securities Schedule of Temporary Impairment Losses, Investments [Table Text Block] Interest income recognized on securities Investment Income [Table Text Block] Amortized cost, carrying value and fair value of securities presented by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Unrealized and realized gains (losses) recognized in net income on equity investments Gain (Loss) on Securities [Table 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] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Share-based Compensation Award, Tranche One Share-based Compensation Award, Tranche One [Member] Share-based Compensation Award, Tranche Two Share-based Compensation Award, Tranche Two [Member] Share-based Compensation Award, Tranche Three Share-based Compensation Award, Tranche Three [Member] Plan Name [Axis] Plan Name [Axis] Plan Name Plan Name [Domain] Incentive Plan 2017 Incentive Plan 2017 [Member] Incentive Plan 2017 [Member] Incentive Plan 2009 Incentive Plan 2009 [Member] Name of the equity-based compensation arrangement plan. Incentive Plan Incentive Plan [Member] Incentive Plan [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Nonqualified Stock Options (NQSO) Employee Stock Option [Member] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Common stock shares reserved and available for issuance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Number of additional shares (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Remaining Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Remaining Shares Authorized Shares remaining available for grant for future awards (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Weighted average exercise price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Awards contractual term Arrangement by Share-based Payment Award, Expiration Period Arrangement by Share-based Payment Award, Expiration Period Awards vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Fair value of shares granted Share based Compensation Arrangements, Non Option Equity Instruments, Granted, Fair Value Share based Compensation Arrangements, Non Option Equity Instruments, Granted, Fair Value Share-based compensation expense Allocated Share-based Compensation Expense The components of net periodic benefit cost Schedule of Net Benefit Costs [Table Text Block] Statement of Cash Flows [Abstract] OPERATING ACTIVITIES: Payments for Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash provided by operations: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and net amortization Depreciation, Depletion and Amortization Securities premium amortization (discount accretion), net Accretion (Amortization) of Discounts and Premiums, Investments Loan (discount accretion) premium amortization, net Investment Income, Net, Amortization of Discount and Premium Provision for loan losses Stock compensation expense Share-based Compensation Deferred tax expense Deferred Income Tax Expense (Benefit) Net loss (gain) on sale of securities available for sale Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Net loss on premises and equipment Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Gross proceeds from sales of loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Gross originations of loans held for sale Payments for Origination and Purchases of Loans Held-for-sale Net loss (gain) on other real estate owned Gains (Losses) on Sales of Other Real Estate Net gain on sale of customer receivables Loans and Leases Receivable, Gain (Loss) on Sales, Net Net change in: Increase (Decrease) in Operating Capital [Abstract] Interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Other assets Increase (Decrease) in Other Operating Assets Interest payable Increase (Decrease) in Interest Payable, Net Other liabilities Increase (Decrease) in Other Operating 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] Securities available for sale: Debt Securities, Available-for-sale [Abstract] Purchases Payments to Acquire Available-for-sale Securities Sales Proceeds from Sale of Available-for-sale Securities Maturities, calls and principal repayments Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Securities held to maturity: Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract] Purchases Payments to Acquire Held-to-maturity Securities Maturities, calls and principal repayments Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Proceeds from redemption of FHLB stock and other investments Proceeds from Sale of Federal Reserve Bank Stock Purchases of FHLB stock and other investments Payments to Acquire Federal Reserve Bank Stock Net loan paydowns (originations) Payments for (Proceeds from) Loans and Leases Proceeds from sales of customer receivables Proceeds from Sale of Loans Receivable Purchases of premises and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sales of premises and equipment Proceeds from Sale of Property, Plant, and Equipment Proceeds from sales of other real estate owned Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans Proceeds from sales of repossessed assets Proceeds from Sale of Foreclosed Assets Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in deposits Net Change Interest and Noninterest-bearing Deposits, Domestic Net (decrease) increase in federal funds purchased and repurchase agreements Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net Proceeds from FHLB borrowings Proceeds from FHLBank Borrowings, Financing Activities Repayment of FHLB borrowings Payments of FHLBank Borrowings, Financing Activities Proceeds from stock option exercises Proceeds from Stock Options Exercised Cash paid to tax authority related to tax withholding on share-based awards Payments Related to Tax Withholding for Share-based Compensation Proceeds from the issuance of common stock for dividend reinvestment plan Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan Cash dividends paid Payments of Ordinary Dividends, Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease) increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period SUPPLEMENTAL DISCLOSURES FOR CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid, Including Capitalized Interest, Operating and Investing Activities Income taxes paid Income Taxes Paid SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES: Noncash Investing and Financing Items [Abstract] Loans transferred to other repossessed assets and real estate through foreclosure Loans transferred to other repossessed assets and real estate through foreclosure The acquisition of assets and real estate received in full or partial satisfaction of a receivable including real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts. Loans transferred from portfolio to held for sale Transfer of Portfolio Loans and Leases to Held-for-sale Transfer of held to maturity securities to available for sale securities Debt Securities, Held-to-maturity, Transfer, Amount Adjustment to pension liability Adjustment to pension liability Adjustment to pension liability during the period related to benefit plans, before tax. Stock dividend (2.5% for 2017) Dividends, Stock Unsettled trades to purchase securities Unsettled issuances of brokered certificates of deposit Summary of fair value measurement on recurring and nonrecurring basis segregated by level of valuation inputs within fair value hierarchy utilized to measure fair value Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Financial assets, financial liabilities, and unrecognized financial instruments at carrying amount and fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Accounting Changes and Error Corrections [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast Scenario, Forecast [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2017-08 Accounting Standards Update 2017-08 [Member] Amortization expense Amortization Cumulative Effect on Retained Earnings, before Tax Cumulative Effect on Retained Earnings, before Tax Share-based Incentive Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Pass Pass [Member] Pass Watch Pass Watch [Member] A category of financing receivables not considered to be special mention, substandard, doubtful, and loss receivables. Special Mention Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Financing Receivable, Recorded Investment [Line Items] Financing Receivable, Recorded Investment, Credit Quality Indicator [Abstract] Financing Receivable Recorded Investment By Credit Quality Indicator [Abstract] -- None. No documentation exists for this element. -- Loans Purchased credit impaired loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury US Treasury Securities [Member] Residential MBS Commercial MBS Equity Investments Interest Rate Swap Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Securities available for sale, at estimated fair value Debt Securities, Available-for-sale Equity investments Equity Securities, FV-NI, Cost Securities available for sale, at estimated fair value Available-for-sale Securities Derivative assets Derivative Asset Derivative liabilities Derivative Liability Foreclosed assets Repossessed Assets Impaired loans Impaired Financing Receivable, Recorded Investment Total asset fair value measurements Assets, Fair Value Disclosure Total liability fair value measurements Financial Liabilities Fair Value Disclosure Current income tax expense Current Income Tax Expense (Benefit) Deferred income tax expense Income tax expense Loans and Allowance for Probable Loan Losses Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Business Combinations [Abstract] Business Combination Disclosure Business Combination Disclosure [Text Block] Schedule of Debt Schedule of Debt [Table Text Block] Schedule of Maturities of Borrowings Schedule of Maturities of Borrowings [Table Text Block] [Table Text Block] for Tabular disclosure of the combined aggregate amount of maturities for all borrowings for each of the five years following the date of the latest balance sheet date presented. Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Statement of Stockholders' Equity [Abstract] Issuance of common stock - DRIP (in shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan Dividends paid on common stock (in dollars per share) Net issuance of common stock under employee stock plans (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Common Stock Dividends, Shares Common Stock Dividends, Shares Schedule of Shares Issued in Connection With Stock Compensation Awards Share-based Compensation, Activity [Table Text Block] Less than 1 Year Borrowed Funds Maturities Repayments of Principal in the Next Twelve Months Borrowed Funds Maturities Repayments of Principal in the Next Twelve Months 1-2 Years Borrowed Funds Maturing in Year Two Amount of borrowed funds maturing in year two following the date of the latest balance sheet presented in the financial statements. 2-3 Years Borrowed Funds Maturing in Year Three Amount of borrowed funds maturing in year three following the date of the latest balance sheet presented in the financial statements. 3-4 Years Borrowed Funds Maturing in Year Four Amount of borrowed funds maturing in year four following the date of the latest balance sheet presented in the financial statements. 4-5 Years Borrowed Funds Maturing in Year Five Amount of borrowed funds maturing in year five following the date of the latest balance sheet presented in the financial statements. Thereafter Borrowed Funds Maturing After Year Five Amount of borrowed funds maturities after year five following the date of the latest balance sheet presented in the financial statements. Total Debt and Capital Lease Obligations Statement of Financial Position [Abstract] Held-to-maturity Securities, Other Disclosure Items [Abstract] Debt Securities, Held-to-maturity, Parenthetical Disclosure [Abstract] Securities held to maturity, fair value Debt Securities, Held-to-maturity, Fair Value LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Shareholders' equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [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 Treasury stock (in shares) Treasury Stock, Shares Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Fair Value Hedging [Member] Fair Value Hedging [Member] Debt Security Category [Axis] Debt Security Category [Axis] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments [Domain] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments [Domain] Available-for-sale Securities [Member] Available-for-sale Securities [Member] Fixed rate callable securities Fixed rate callable securities [Member] Fixed rate callable securities [Member] Energy [Axis] Energy [Axis] Energy [Domain] Energy [Domain] Position [Axis] Position [Axis] Position [Domain] Position [Domain] Derivative [Line Items] Derivative [Line Items] Hedged asset, fair value hedge Hedged Asset, Fair Value Hedge Debt instrument, face amount Cash collateral received from counterparties under master netting agreements Derivative Asset, Collateral, Obligation to Return Cash, Offset Interest Receivable on Impaired Loans [Abstract] Interest Receivable on Impaired Loans [Abstract] Average recorded investment Impaired Financing Receivable, Average Recorded Investment Interest income recognized Impaired Financing Receivable, Interest Income, Cash Basis Method Derivative Financial Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method [Table] Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method [Table] Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method [Table] Credit Loss Status [Axis] Credit Loss Status [Axis] Credit Loss Status [Domain] Credit Loss Status [Domain] Financial Asset Acquired with Credit Deterioration [Member] Financial Asset Acquired with Credit Deterioration [Member] Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method [Line Items] Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method [Line Items] [Line Items] for Schedule of Allowance For Loan Losses, Allowance Balance, by Impairment Method Loans and Leases Receivable, Allowance Loans and Leases Receivable, Allowance Ending balance - individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Ending balance - collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Balance at end of period Financing Receivable, Allowance for Credit Losses Organization, Consolidation and Presentation of Financial Statements [Abstract] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Securities Investment, Policy [Policy Text Block] Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract] Owner and nonowner-occupied real estate Commercial Real Estate, Commercial Real Estate Commercial Real Estate, Commercial Real Estate Loans secured by multi-family properties Commercial Real Estate, Multifamily Commercial Real Estate, Multifamily Loans secured by farmland Commercial Real Estate, Farm Land Commercial Real Estate, Farm Land Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Loan review larger dollar loan relationship scope, aggregate debt Loan Review Larger Dollar Loan Relationship Scope, Aggregate Debt LoanReviewLargerDollarLoanRelationshipScope_AggregateDebt [Text Block] The loan review scope as it relates to size, focuses more on larger dollar loan relationships Specifically reserved loans or loan relationships threshold Specifically Reserved Loans or Loan Relationships Threshold Specifically Reserved Loans or Loan Relationships Threshold Loans in process of foreclosure Loans in Process of Foreclosure Loans in Process of Foreclosure Loans and leases receivable, impaired, commitment to lend Loans and Leases Receivable, Impaired, Commitment to Lend Impaired loans without an allowance Impaired Financing Receivable, with No Related Allowance, Recorded Investment U.S. Treasury Interest Income, Securities, US Treasury U.S. Government Agency Debentures Interest Income, Securities, Other US Government State and Political Subdivisions Interest Income, Securities, State and Municipal Other Stocks and Bonds Interest Income, Other Stocks and Bonds Represents interest income, including any amortization and accretion (as applicable) of discounts and premiums, derived from securities backed by other stocks and bonds. Other Equity Securities Interest income, Other Equity Securities Interest income on other equity securities Mortgage-backed Securities Total interest income on securities Interest and Other Income Document and Entity Information [Abstract] -- None. No documentation exists for this element. -- Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Document Type Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Amendment Flag Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Entity Common Stock, Shares Outstanding Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Schedule of accumulated other comprehensive income (loss) by component Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassifications out of accumulated other comprehensive income Reclassification out of Accumulated Other Comprehensive Income [Table 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] Defined Benefit Pension Plan Pension Plan [Member] Defined Benefit Pension Plan Acquired Other Pension Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Contributions by Employer Defined Benefit Plan, Plan Assets, Contributions by Employer Earnings per share on a basic and diluted basis Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] US Treasury Securities [Member] AVAILABLE FOR SALE Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Gross unrealized gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Estimated fair value Amortized Cost Available-for-sale Securities, Amortized Cost Basis 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 Estimated fair value HELD TO MATURITY Debt Securities, Held-to-maturity [Abstract] Amortized cost Debt Securities, Held-to-maturity Gross unrealized gains Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain Gross unrealized losses Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss Estimated Fair Value AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Unrealized losses on securities transferred from held to maturity to available for sale: Securities Transferred Between Held-to-Maturity And Available-for-Sale Securities [Member] Securities Transferred Between Held-to-Maturity And Available-for-Sale Securities [Member] Unrealized gains and losses on available for sale securities Reclassifications out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of accumulated other comprehensive income Reclassification out of Accumulated Other Comprehensive Income [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Unrealized gains (losses) Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Realized net loss on interest rate swap derivatives Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Amortization of unrealized gains on terminated interest rate swap derivatives Accumulated Net Gain Loss From Terminated Interest Rate Swap Derivatives [Member] Accumulated Net Gain Loss From Terminated Interest Rate Swap Derivatives [Member] Net actuarial loss Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Prior service credit Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Amortization of pension plan Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Amortization of unrealized losses Amortization of Unrealized Gains (Losses) on Securities Transferred Between Available-for-Sale And Held to Maturity Debt Securities, Before Tax Amortization of Unrealized Gains (Losses) on Securities Transferred Between Available-for-Sale And Held to Maturity Debt Securities, Before Tax Tax benefit (expense) Net of tax Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Realized net (loss) gain on sale of securities Gain (Loss) on Investments, Excluding Other than Temporary Impairments Realized net gain (loss) on interest rate swap derivatives Interest Income (Expense), Nonoperating, Net Reclassified from accumulated other comprehensive income Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Tax benefit Reclassification from AOCI, Current Period, Tax Total reclassifications for the period, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Class of Financing Receivable [Axis] Allowances for Loan Losses [Roll Forward] Allowance for Loan and Lease Losses [Roll Forward] Balance at beginning of period Provision (reversal) for loan losses Provision (Reversal) for Loan, Lease, and Other Losses Provision (Reversal) for Loan, Lease, and Other Losses Loans charged off Financing Receivable, Allowance for Credit Losses, Write-downs Recoveries of loans charged off Financing Receivable, Allowance for Credit Losses, Recovery Balance at end of period Provision for PCI Loans Provision for PCI Loans Provision for PCI Loans Nonperforming Assets by Asset Class [Abstract] Loans and Leases Receivable Disclosure [Abstract] Nonaccrual loans Financing Receivable, Recorded Investment, Nonaccrual Status Accruing loans past due more than 90 days Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Restructured loans Financing Receivable, Modifications, Recorded Investment Other real estate owned Real Estate Acquired Through Foreclosure Repossessed assets Other Repossessed Assets Total Nonperforming Assets Financing Receivable, Net Number of commercial real estate relationships added to nonaccrual Number of commercial real estate relationships added to nonaccrual Number of commercial real estate relationships added to nonaccrual Number of commercial real estate loans added to nonaccrual Number of commercial real estate loans added to nonaccrual Number of commercial real estate loans added to nonaccrual PCI loans restructured Purchase Credit Impaired Loans Restructured Purchase Credit Impaired Loans Restructured Accumulated Other Comprehensive Income by Component, Changes [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accounting Standards Update 2016-01 Accounting Standards Update 2016-01 [Member] Retained Earnings Retained Earnings [Member] Unrealized Gains (Losses) on Securities Unrealized Gains (Losses) on Derivatives Net Prior Service (Cost) Credit Net Gain (Loss) Total AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income by Component, Changes [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax AOCI Attributable to Parent, Net of Tax [Roll Forward] Beginning balance, net of tax Stockholders' Equity Attributable to Parent Other comprehensive (loss) income before reclassifications Other Comprehensive Income (Loss), before Reclassifications, before Tax Reclassified from accumulated other comprehensive income Income tax benefit (expense) Other Comprehensive Income (Loss), Tax Net current-period other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Ending balance, net of tax Cumulative effect of new accounting principle before tax Cumulative Effect of New Accounting Principle in Period of Adoption, Before Tax Cumulative Effect of New Accounting Principle in Period of Adoption, Before Tax Cumulative effect of new accounting principle Cumulative Effect of New Accounting Principle in Period of Adoption Statement of Comprehensive Income [Abstract] Net income Other comprehensive (loss) income: Other Comprehensive Income (Loss), Net of Tax [Abstract] Securities available for sale and transferred securities: Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract] Change in net unrealized holding (losses) gains on available for sale securities during the period Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Unrealized net gain on securities transferred from held to maturity to available for sale under the transition guidance enumerated in ASU 2017-12 Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax Change in net unrealized losses on securities transferred from held to maturity to available for sale Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Securities Transferred from Held to Maturity to Available for Sale Arising During Period, Before Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Securities Transferred from Held to Maturity to Available for Sale Arising During Period, Before Tax Reclassification adjustment for net loss on equity investments, reclassified to retained earnings with adoption of ASU 2016-01 Other Comprehensive Income (Loss), Reclassification Adjustment for Net Loss on Equity Security, Reclassified To Retained Earnings Net Income with the adoption of ASU 2016-01 Other Comprehensive Income (Loss), Reclassification Adjustment for Net Loss on Equity Security, reclassified to Retained Earnings with the adoption of ASU 2016-01 Reclassification adjustment for amortization related to available for sale and held to maturity debt securities Reclassification adjustment for net loss (gain) on sale of available for sale securities, included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Derivatives: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax [Abstract] Change in net unrealized gain (loss) on effective cash flow hedge interest rate swap derivatives Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Change in net unrealized gains on interest rate swap derivatives terminated during the period Other Comprehensive Income, Unrealized Gain Loss On Terminated Derivatives During Period, Before Tax Other Comprehensive Income, Unrealized Gain Loss On Terminated Derivatives During Period, Before Tax Reclassification adjustment from other comprehensive income (loss) related to derivatives designated as cash flow hedge Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Pension plans: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract] Amortization of net actuarial loss and prior service credit, included in net periodic benefit cost Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) and Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) and Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Other comprehensive (loss) income, before tax Other Comprehensive Income (Loss), before Tax Income tax benefit (expense) related to items of other comprehensive income (loss) Other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] New shares issued from available authorized shares Common Stock [Member] New shares issued from available treasury shares Treasury Stock [Member] New shares issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Proceeds from stock option exercises Borrowing Arrangements Debt Disclosure [Text Block] Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Benefit, Adjustment Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit), Adjustment Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit), Adjustment Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax Net deferred tax assets Deferred Tax Assets, Net Deferred tax assets, valuation allowance Deferred Tax Assets, Valuation Allowance Effective income tax rate, percent Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Purchased Credit Impaired [Abstract] Purchased Credit Impaired [Abstract] Purchased Credit Impaired [Abstract] Outstanding principal balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Carrying amount Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Certain Loans Acquired in Transfer Not 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 Changes in expected cash flows not affecting non-accretable differences Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Period Increase (Decrease) Reclassifications (to) from nonaccretable discount Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Balance at end of period Classification of loans in the consolidated balance sheets Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Activity in the allowance for loan losses by portfolio segment Allowance for Credit Losses on Financing Receivables [Table Text Block] Balance in the allowance for loan losses by portfolio segment based on impairment method Balance in the allowance for loan losses and recorded investment in loans by portfolio segment based on impairment method [Table Text Block] Tabular disclosure of balance in the allowance for loan losses and recorded investment in loans by portfolio segment. Balance in recorded investments in loans by portfolio segment based on impairment method Impaired Financing Receivables [Table Text Block] Summary of loans by credit quality indicators Financing Receivable Credit Quality Indicators [Table Text Block] Summary of nonperforming assets for the period Summary of nonperforming assets for the period [Table Text Block] Tabular disclosure of nonperforming assets. Recorded investment in nonaccrual by class of loans Past Due Financing Receivables [Table Text Block] Summary of impaired loans by class of loans for the period Summary of impaired loans by class of loans for the period [Table Text Block] Tabular disclosure of impaired loans by class of loans for the period. Aging of recorded investment in past due loans by class of loans Aging of recorded investment in past due loans by class of loans [Table Text Block] Tabular disclosure of recorded investment in past due loans by class of loans. Average recorded investment and interest income on impaired loans Summary of impaired loans, primarily nonaccrual loans [Table Text Block] Tabular disclosure of nonaccrual impaired loans. Schedule of recorded investment in loans modified Troubled Debt Restructurings on Financing Receivables [Table Text Block] Schedule of PCI Loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table Text Block] Schedule of changes in accretable yield for pci loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities AccretableYield Movement [Table Text Block] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities AccretableYield Movement [Table Text Block] AVAILABLE FOR SALE Available-for-sale Securities, Debt Maturities [Abstract] Available for sale, Amortized Cost Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Due in one year or less Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Due after ten years Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Total available-for-sale investment securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Mortgage-backed Securities Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Available for sale, Fair Value Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] Due in one year or less Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Due after ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Total available-for-sale investment securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Mortgage-backed Securities Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Total HELD TO MATURITY Debt Securities, Held-to-maturity, Maturity [Abstract] Held to maturity, Amortized Cost Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract] Due in one year or less Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Due after one year through five years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Due after five years through ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Due after ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost Total held-to-maturity investment securities Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost Mortgage-backed securities Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Amortized Cost Held to maturity, Fair Value Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract] Due in one year or less Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due after one year through five years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Due after five years through ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Due after ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Total held-to-maturity investment securities Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value Mortgage-backed securities Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value Fair Value Restoration Plan Other Pension, Postretirement and Supplemental Plans [Member] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Net loss amortization Defined Benefit Plan, Amortization of Gain (Loss) Prior service (credit) cost amortization Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Net periodic benefit cost (income) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) ASSETS Assets [Abstract] Cash and due from banks Cash and Due from Banks Interest earning deposits Interest-bearing Deposits in Banks and Other Financial Institutions Federal funds sold Federal Funds Sold Total cash and cash equivalents Securities held to maturity, at carrying value (estimated fair value of $156,472 and $921,800, respectively) FHLB stock, at cost Federal Home Loan Bank Stock Equity investments Equity Securities, FV-NI and without Readily Determinable Fair Value Equity investments Equity Securities without Readily Determinable Fair Value, Amount Loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Loans: Loans and Leases Receivable, Net Amount [Abstract] Less: Allowance for loan losses Net Loans Loans and Leases Receivable, Net Amount Premises and equipment, net Property, Plant and Equipment, Net Goodwill Goodwill Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Interest receivable Interest Receivable Deferred tax asset, net Deferred Tax Assets, Net of Valuation Allowance Bank owned life insurance Bank Owned Life Insurance Other assets Other Assets Total assets Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Noninterest bearing Noninterest-bearing Deposit Liabilities Interest bearing Interest-bearing Deposit Liabilities Total deposits Deposits Subordinated notes, net of unamortized debt issuance costs Other liabilities Other Liabilities Total liabilities Liabilities Off-balance-sheet arrangements, commitments and contingencies (Note 13) Commitments and Contingencies Shareholders’ equity: Common stock: ($1.25 par value, 80,000,000 shares authorized and 37,832,989 shares issued at September 30, 2018 and 40,000,000 shares authorized and 37,802,352 shares issued at December 31, 2017) Common Stock, Value, Issued Paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock, shares at cost (2,673,050 at September 30, 2018 and 2,802,019 at December 31, 2017) Treasury Stock, Value Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total shareholders’ equity Total liabilities and shareholders’ equity Liabilities and Equity Summary of Significant Accounting and Reporting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Schedule of Business Acquisitions, by Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Off-Balance-Sheet Arrangements, Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Common Stock Paid In Capital Additional Paid-in Capital [Member] Treasury Stock Accumulated Other Comprehensive Income (Loss) Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Other comprehensive income (loss) Issuance of common stock for dividend reinvestment plan (30,637 shares in 2018 and 33,000 shares in 2017) Stock Issued During Period, Value, Dividend Reinvestment Plan Stock compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Net issuance of common stock under employee stock plans (128,969 shares in 2018 and 138,035 shares in 2017) Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Cash dividends paid on common stock ($0.88 per share in 2018 and $0.81 per share in 2017) Dividends, Common Stock, Cash Cumulative effect of ASU 2016-01 Stock dividend declared (719,515 shares in 2017) Dividends, Common Stock, Stock Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] 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] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Cash Flow Hedging Cash Flow Hedging [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Notional Amount Derivative, Notional Amount Asset Derivative Derivative Asset [Abstract] Gross derivatives Derivative Asset, Fair Value, Gross Asset Offsetting derivative assets Derivative Asset, Fair Value, Gross Liability Cash collateral received/posted Net derivatives included in the consolidated balance sheets Liability Derivative Derivative Liability [Abstract] Gross derivatives Derivative Liability, Fair Value, Gross Liability Offsetting derivative liabilities Derivative Liability, Fair Value, Gross Asset Cash collateral received/posted Derivative Liability, Collateral, Right to Reclaim Cash, Offset Net derivatives included in the consolidated balance sheets Net credit exposure Derivative Credit Risk Valuation Adjustment, Derivative Assets New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Principles, Early Adoption [Domain] New Accounting Principles, Early Adoption [Domain] New Accounting Pronouncement, Early Adoption, Effect New Accounting Pronouncement, Early Adoption, Effect [Member] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2017-07 Accounting Standards Update 2017-07 [Member] Accounting Standards Update 2017-12 Accounting Standards Update 2017-12 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Decrease in debit card expense Decrease in brokerage expense Brokerage expense Brokerage expense Decrease in brokerage services income Increase in salaries and employee benefits expense Decrease in other Noninterest Expense Securities available for sale Held-to-maturity securities Decrease in deposit services income Revenue from Contract with Customer, Excluding Assessed Tax Basic and Diluted Earnings: Net Income (Loss) Attributable to Parent [Abstract] Basic weighted-average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Add: Stock awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted weighted-average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Basic Earnings Per Share: Earnings Per Share, Basic [Abstract] Earnings per common share - basic (in dollars per share) Diluted Earnings Per Share: Earnings Per Share, Diluted [Abstract] Earnings per common share - diluted (in dollars per share) Antidilutive securities excluded from calculating earnings Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Number of antidilutive options (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Financing Receivable, Modifications [Line Items] Extend Amortization Period Loan modification related to extending amortization period The amount of modified outstanding recorded investment related to extending amortization period. Interest Rate Reductions Loan modification related to interest rates reductions The amount of modified outstanding recorded investment related to interest rates reductions. Combination Loan modification extending amortization period, lowering interest rate, and principal forgiveness The amount of the modified outstanding recorded investment related to amortization period, lowering interest rate, and principal forgiveness of loans. Total Modifications Financing Receivable, Modifications, Total Modifications for the Period Financing Receivable, Modifications, Total Modifications for the Period Number of Loans Financing Receivable, Modifications, Number of Contracts Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Purchase Credit Impaired (PCI) Loans Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Loans and Leases Receivable Disclosure [Abstract] Total ending loan balance Less: Allowance for loan losses Net Loans Investment [Table] Investment [Table] Investment [Line Items] Investment [Line Items] Transferred Securities, Unrealized Loss, Before Tax Transferred Securities, Unrealized Loss, Before Tax Transferred Securities, Unrealized Loss, Before Tax Securities transferred, Unrealized Loss, Net of Tax Securities transferred, Unrealized Loss, Net of Tax Securities transferred, Unrealized Loss, Net of Tax Fair value of securities transferred from AFS to HTM Securities Transferred From Available for Sale to Held to Maturity Securities Transferred From Available for Sale to Held to Maturity Unrealized net gain on securities transferred from held to maturity to available for sale, before tax Unrealized net gain on securities transferred from held to maturity to available for sale, net of tax Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax AFS securities and HTM securities with other-than-temporary impairment AFS securities and HTM securities with other-than-temporary impairment AFS securities and HTM securities with other-than-temporary impairment Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract] Net realized (loss) gain on AFS securities Debt Securities, Available-for-sale, Realized Gain (Loss) Gross realized gains on AFS securities Debt Securities, Available-for-sale, Realized Gain Gross realized loss on AFS securities Debt Securities, Available-for-sale, Realized Loss Carrying value of investment securities pledged as collateral Pledged Financial Instruments, Not Separately Reported, Securities Equity investments Equity investments without readily determinable fair value Unrealized losses on equity investment included in AFS securities Available-for-sale Securities, Accumulated Gross Unrealized Loss, Net of Tax Available-for-sale Securities, Accumulated Gross Unrealized Loss, Net of Tax Equity investments with other-than-temporary impairment Equity investments with other-than-temporary impairment Equity investments with other-than-temporary impairment Debt Securities, Held-to-maturity, Sale or Transfer of Investment [Abstract] Debt Securities, Held-to-maturity, Sale or Transfer of Investment [Abstract] Sale of HTM portfolio Proceeds from Sale of Held-to-maturity Securities Remaining Maturity (in years) Derivative, Average Remaining Maturity Weighted Average Receive Rate Derivative, Weighted Average Receive Rate Derivative, Weighted Average Receive Rate Weighted Average Pay Rate Derivative, Weighted Average Pay Rate Derivative, Weighted Average Pay Rate Schedule of Financing Receivables Past Due [Table] Schedule of Allowance For Loan Losses, Loan Balance, by Impairment Method [Table]