Fair Value Disclosures [Abstract] Schedule of Fair Value, Off-balance Sheet Risks [Table] Schedule of Fair Value, Off-balance Sheet Risks [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Commitments to Extend Credit [Axis] Commitments to Extend Credit [Axis] This represents commitments to extend credit. Commitments to Extend Credit [Domain] Commitments to Extend Credit [Domain] This represents commitments to extend credit. Commitments to extend credit on commerical loans [Member] Commitments to Extend Credit on Commerical Loans [Member] This represents commitments to extend credit on commerical loans. Commitments to extend credit on home equity lines [Member] Commitments to Extend Credit on Home Equity Lines [Member] This represents commitments to extend credit on home equity lines. Commitments to extend credit on other loans [Member] Commitments to Extend Credit on Other Loans [Member] This represents commitments to extend credit on other loans. Commitments to extend credit on standby letters of credit [Member] Commitments to Extend Credit on Standby Letters of Credit [Member] This represents commitments to extend credit on standby letters of credit. Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Interest rate lock commitments [Member] Interest Rate Lock Commitments [Member] Forward sale commitments [Member] Forward Contracts [Member] Interest rate swaps with customers [Member] Interest Rate Swap with customers [Member] Interest Rate Swap with customers [Member] Mirror swaps with counterparties [Member] Interest Rate Mirror Swaps with Counterparties [Member] This category includes interest rate mirror swaps with counterparties. Risk participation-in agreement [Member] Risk participation-in agreement [Member] Risk participation-in agreement [Member] - Represents the agreement the Corporation has with another bank, where the Corporation is participating in a commercial loan arrangement and the participating bank guarantees the performance on a borrower-related interest rate swap contract. Foreign exchange contracts [Member] Foreign Exchange Contract [Member] Interest rate swaps [Member] Interest Rate Swap [Member] Fair Value, Off-balance Sheet Risks by Financial Instrument [Axis] Financial Instrument [Axis] Fair Value, Off-balance Sheet Risks, Financial Instruments [Domain] Financial Instruments [Domain] Commitments to extend credit [Member] Commitments to Extend Credit [Member] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Contract amount Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Asset Notional amount Derivative, Notional Amount New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Operating Leases, Future Minimum Payments Due Operating Leases, Future Minimum Payments Due Commitments and Contingencies Disclosure [Abstract] Financial Instruments with Off Balance Sheet Risk Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block] Schedule of Future Minimum Annual Lease Payments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Receivables [Abstract] Weighted Average Commercial Loan Portfolio Risk Rating Weighted Average Risk Rating, Commercial Loans The represents the weighted average risk rating for commercial loans. 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] Summary of information required and determined to be disclosed concerning available for sale and held to maturity securities which consist of all investments in certain debt and equity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] 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] Individual name issuer trust preferred debt securities Trust Preferred Securities Individual Name Issuers [Member] This category includes trust preferred securities individual name issuers. Corporate bonds [Member] Corporate Bond Securities [Member] Schedule of Available for Sale and Held to Maturty Securities [Line Items] Schedule of Available for Sale and Held to Maturty Securities [Line Items] Line items for schedule of Available for Sale and Held to Maturty Securities. Fair value of available for sale and held to maturity securities pledged as collateral Security Owned and Pledged as Collateral, Fair Value Amortized cost of callable debt securities Callable Debt Securities Amortized Cost This represents the amortized cost for callable debt securities. Fair value of callable debt securities Callable Debt Securities Fair Value This represents the fair value for callable debt securities. Maturity period of callable debt securities Callable Debt Securities, Maturity Period Callable Debt Securities, Maturity Period Call features of callable debt securities Callable Debt Securities, Call Feature, Period Callable Debt Securities, Call Feature, Period Number of securities in a continuous unrealized loss position total Available-for-sale Securities, Continuous Unrealized Loss Position, Total, Number This item represents the number of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position. Securities in unrealized loss position, number of companies issuing securities Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Companies Issuing Securities Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Companies Issuing Securities Amortized cost of trust preferred securities of individual name issuers that are below investment grade Trust Preferred Securities Individual Name Issuer Amortized Cost Below Investment Grade This represents the amortized cost for trust preferred securities for individual name issuers that are below investment grade. Unrealized losses of trust preferred securities of individual name issuers that are below investment grade Trust Preferred Securities Individual Name Issuer Unrealized Losses Below Investment Grade This represents the unrealized losses for trust preferred securities for individual name issuers that are below investment grade. Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments Loans Receivable Net Deferred Cost Originated Loans Receivable Net Deferred Cost Originated Reflects cumulative amount of net costs paid by borrowers which have not been taken into expense. Loans Receivable Net Deferred Premium on Purchased Loans Loans Receivable Net Deferred Premium on Purchased Loans Reflects premiums over or discounts from face amounts of acquired loans that are being amortized into income as an adjustment to yield. Loans Pledged as Collateral Loans Pledged as Collateral Past due loans included in nonaccrual loans Loans Receivable, Past Due, Nonaccrual Reflects carrying value of loans which are past due and on nonaccrual status. Mortgage Loans in Process of Foreclosure Mortgage Loans in Process of Foreclosure, Amount Statement of Financial Position [Abstract] Assets: Assets [Abstract] Cash and due from banks Cash and Due from Banks Short-term investments Other Short-term Investments Mortgage loans held for sale, at fair value Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage Securities: Marketable Securities [Abstract] Available for sale, at fair value Available-for-sale Securities Held to maturity, at amortized cost Held-to-maturity Securities Total securities Marketable Securities Federal Home Loan Bank stock, at cost Federal Home Loan Bank Stock Loans: Loans and Leases Receivable, Net Amount [Abstract] Total loans Loans and Leases Receivable, Net of Deferred Income Less allowance for loan losses Loans and Leases Receivable, Allowance Net loans Loans and Leases Receivable, Net Amount Premises and equipment, net Property, Plant and Equipment, Net Investment in bank-owned life insurance Bank Owned Life Insurance Goodwill Goodwill Identifiable intangible assets, net Intangible Assets, Net (Excluding Goodwill) Other assets Other Assets Total assets Assets Liabilities: Liabilities [Abstract] Noninterest-bearing deposits Noninterest-bearing Deposit Liabilities Interest-bearing deposits Interest-bearing Deposit Liabilities Total deposits Deposits Federal Home Loan Bank advances Advances from Federal Home Loan Banks Junior subordinated debentures Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Other liabilities Other Liabilities Total liabilities Liabilities Commitments and contingencies (Note 18) Commitments and Contingencies Shareholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total shareholders' equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders’ equity Liabilities and Equity Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Obligations of U.S. government-sponsored enterprises [Member] US Government-sponsored Enterprises Debt Securities [Member] Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Obligations of states and political subdivisions [Member] US States and Political Subdivisions Debt Securities [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] Available for sale securities Mortgage loans held for sale, measured at fair value Loans Held-for-sale, Fair Value Disclosure Derivative assets Derivative Asset Total assets at fair value on a recurring basis Assets, Fair Value Disclosure Derivative liabilities Derivative Liability Contingent consideration liability Business Combination, Contingent Consideration, Liability Total liabilities at fair value on a recurring basis Financial and Nonfinancial Liabilities, Fair Value Disclosure Earnings Per Share [Abstract] Net income Net Income (Loss) Attributable to Parent Less dividends and undistributed earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Net income applicable to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Weighted average common shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Basic earnings per common share Earnings Per Share, Basic Less dividends and undistributed earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted Net income applicable to common shareholders Net Income (Loss) Available to Common Stockholders, Diluted Dilutive effect of common stock equivalents Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average common shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Diluted earnings per common share Earnings Per Share, Diluted Antidilutive common stock equivalents Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Domain] Class of Financing Receivable, Type [Domain] Commercial Real Estate Commercial Real Estate Portfolio Segment [Member] Commercial & Industrial Commercial Other [Member] Class of financing receivables related to commercial and industrial financing receivables Total Commercial Commercial Portfolio Segment [Member] Residential Real Estate Residential Portfolio Segment [Member] Home Equity Home equity [Domain] Portfolio segment of the company's total financing receivables related to home equity lines and loans. Other Other consumer [Domain] Portfolio segment of the company's total financing receivables related to other consumer loans that are not home equity lines or loans. Total Consumer Consumer Portfolio Segment [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Loans individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Loans related allowance individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Loans collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Loans related allowance collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Allowance Financing Receivable, Allowance for Credit Losses Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Payment Default [Member] Payment Default [Member] Payment Default [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Number of loans modified as a troubled debt restructuring Financing Receivable, Modifications, Number of Contracts Recorded investment on TDR modifications with payment default Financing Receivable, Modifications, Subsequent Default, Recorded Investment Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-Based Compensation Arrangements Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Balance Sheet Offsetting [Abstract] Balance Sheet Offsetting [Abstract] Statement [Table] Statement [Table] Derivatives, Fair Value, by Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other assets [Member] Other Assets [Member] Other liabilities [Member] Other Liabilities [Member] Interest rate floors [Member] Interest Rate Floor [Member] Interest rate caps [Member] Interest Rate Cap [Member] Statement [Line Items] Statement [Line Items] Gross derivative positions Derivative Asset, Fair Value, Gross Asset Offsetting derivative positions Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Net amounts presented in balance sheet Derivative Asset, Fair Value, Amount Offset Against Collateral Cash collateral pledged Derivative Asset, Collateral, Obligation to Return Cash, Offset Gross derivative positions Derivative Liability, Fair Value, Gross Liability Offsetting derivative positions Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Net amounts presented in balance sheet Derivative Liability, Fair Value, Amount Offset Against Collateral Cash collateral pledged Derivative, Collateral, Right to Reclaim Cash Net amount Derivative, Fair Value, Amount Offset Against Collateral, Net Summary of Loans Schedule of Loans Receivable [Table Text Block] Tabular disclosure of loans receivable along with percent of total loans. Past Due Loans Past Due Financing Receivables [Table Text Block] Impaired Loans Impaired Financing Receivables [Table Text Block] Nonaccrual Loans Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Credit Quality Indicators Commercial Financing Receivable Credit Quality Indicators [Table Text Block] Credit Quality Indicators Residential & Consumer Loan Receivable, Credit Quality Indicators, Residential & Consumer [Table Text Block] Tabular disclosure of financing receivables by credit quality indicator for residential and consumer loans. The credit quality indicator is a statistic about the credit quality of financing receivables. Allowance for Loan Losses Allowance for Credit Losses [Text Block] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Recorded Investment of Impaired Loans with No Related Allowance Impaired Financing Receivable, with No Related Allowance, Recorded Investment Recorded Investment of Impaired Loans with Related Allowance Impaired Financing Receivable, with Related Allowance, Recorded Investment Total Recorded Investment of Impaired Loans Impaired Financing Receivable, Recorded Investment Unpaid Principal of Impaired Loans with No Related Allowance Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Unpaid Principal of Impaired Loans with Related Allowance Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance Total Unpaid Principal of Impaired Loans Impaired Financing Receivable, Unpaid Principal Balance No Related Allowance on Impaired Loans Impaired Financing Receivable, No Related Allowance Amount of allowance for credit losses related to recorded investment. Related Allowance on Impaired Loans Impaired Financing Receivable, Related Allowance Defined Benefit Plan [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast [Member] Scenario, Forecast [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Qualified Pension Plan [Member] Pension Plan [Member] Non-Qualified Retirement Plans [Member] Supplemental Employee Retirement Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of prior service (credit) cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized net actuarial loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Items Recorded at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Change in Contingent Consideration Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Items Recorded at Fair Value on a Nonrecurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Quantitative Information About Level 3 Assets Measured at Fair Value on a Nonrecurring Basis Fair Value Inputs Assets Nonrecurring Quantitative Information [Table Text Block] Tabular disclosure of quantitative information about the inputs used in the fair value measurement of nonrecurring assets. This disclosure may include, but is not limited to, the fair value of the asset, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs. Carrying Amounts and Estimated Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contracts with Customers Revenue from Contract with Customer [Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] 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 [Member] Portion at Fair Value Measurement [Member] Reported Value Measurement [Member] Reported Value Measurement [Member] Fair Value Measurement [Member] 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] Held to maturity securities Loans, net of allowance of loan losses Time deposits Time Deposits Junior subordinated debentures Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Commercial Mortgages Commercial Real Estate [Member] Commercial Construction & Development Construction Loans [Member] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Pass [Member] Pass [Member] Special Mention [Member] Special Mention [Member] Classified [Member] Classified [Member] A category of financing receivable which includes loans identified as "substandard", "doubtful" or "loss" based on criteria consistent with guidelines provided by banking regulators. Financing Receivable, Recorded Investment [Line Items] Financing Receivable, Recorded Investment [Line Items] Loans Receivable Financing Receivable, Net Equity [Abstract] Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Changes in fair value of securities available for sale, before tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Changes in fair value of securities available for sale, tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Changes in fair value of securities available for sale Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Net gains on securities reclassified into earnings, before tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Net gains on securities reclassified into earnings, tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Net gains on securities reclassified into earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Net change in fair value of securities available for sale, before tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax Net change in fair value of securities available for sale, tax Other Comprehensive Income (Loss), Available-for-sale Securities, Tax Net change in fair value of securities available for sale Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Change in fair value of cash flow hedges, before tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Change in fair value of cash flow hedges, tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Change in fair value of cash flow hedges Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Net cash flow hedge losses reclassified into earnings, before tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Net cash flow hedge losses reclassified into earnings, tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Net cash flow hedge losses reclassified into earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net change in fair value of cash flow hedges, before tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Net change in fair value of cash flow hedges, tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Net change in fair value of cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Defined benefit plan obligation adjustment, before tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Defined benefit plan obligation adjustment, tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Defined benefit plan obligation adjustment Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Amortization of net actuarial losses, before tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Amortization of net actuarial losses, tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax Amortization of net actuarial losses Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Amortization of net prior service credits, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Amortization of net prior service credits, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Amortization of net prior service credits Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Net change in defined benefit plan obligations, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Net change in defined benefit plan obligations, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Net change in defined benefit plan obligations Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Total other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Total other comprehensive income (loss), tax Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Total other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Available for sale debt securities maturities within 1 year amortized cost Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Available for sale debt securities maturities 1-5 years amortized cost Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Available for sale debt securities maturities 5-10 years amortized cost Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Available for sale debt securities maturities after 10 years amortized cost Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Available for sale debt securities maturities total amortized cost Available-for-sale Debt Securities, Amortized Cost Basis Available for sale debt securities maturities within 1 year fair value Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Available for sale debt securities maturities 1-5 years fair value Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Available for sale debt securities maturities 5-10 years fair value Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Available for sale debt securities maturities after 10 years fair value Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Available for sale debt securities fair value Available-for-sale Securities, Debt Securities Held to maturity debt securities maturities within 1 year amortized cost Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount Held to maturity debt securities maturities 1-5 years amortized cost Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount Held to maturity debt securities maturities 5-10 years amortized cost Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount Held to maturity debt securities maturities after 10 years amortized cost Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount Held to maturity securities Held to maturity debt securities maturities within 1 year fair value Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value Held to maturity debt securities maturities 1-5 years fair value Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value Held to maturity debt securities maturities 5-10 years fair value Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value Held to maturity debt securities maturities after 10 years fair value Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value Held to maturity securities fair value Held-to-maturity Securities, Fair Value Statement of Comprehensive Income [Abstract] Other Comprehensive Income (Loss), Net of Tax [Abstract] Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract] Net change in fair value of securities available for sale Net change in fair value of cash flow hedges Net change in defined benefit plan obligations Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivatives Designated as Cash Flow Hedging Instruments [Member] Designated as Hedging Instrument [Member] Risk participation agreements [Member] Risk participation agreements [Member] Risk participation agreements Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative asset designated as a cash flow hedge Interest Rate Cash Flow Hedge Asset at Fair Value Derivative liability designated as a cash flow hedge Interest Rate Cash Flow Hedge Liability at Fair Value Derivative asset not designated Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value Derivative liability not designated Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value Total derivative assets Total derivative liabilities Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Percent of Total Loans Percent of Total Loans Percent of these loans to Total Loans at close of the period. Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net Unrealized Gains (Losses) on AFS Securities [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Net Unrealized Losses on Cash Flow Hedges [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Pension Benefit Adjustment [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Comprehensive Income [Line Items] Accumulated other comprehensive income (loss), beginning balance Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassed from accumulated other comprehensive income (loss) Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Total other comprehensive income (loss), net of tax Accumulated other comprehensive income (loss), ending balance Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) by Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedge [Member] Cash Flow Hedging [Member] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Other Comprehensive Income (Loss) [Member] Other Comprehensive Income (Loss) [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Statement of Stockholders' Equity [Abstract] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) [Member] AOCI Attributable to Parent [Member] Common Stock, Shares Outstanding, Beginning Balance Common Stock, Shares, Outstanding Shareholders' Equity, Beginning Balance Cash dividends declared Dividends, Common Stock, Cash Share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Exercise of stock options and issuance of other compensation-related equity awards, shares ExerciseOfStockOptionsAndIssuanceOfOtherCompensationRelatedEquityInstrumentsShares Shares of stock issued during the period as a result of the exercise of stock options and stock related to other compensation related equity instruments, net of the stock value of such awards forfeited. Exercise of stock options and issuance of other compensation-related equity awards, value Exercise of Stock Options and Issuance of Other Compensation Related Equity Instruments, Value Value of stock issued during the period as a result of the exercise of stock options and value of stock related to restricted stock awards issued during the period, net of the stock value of such awards forfeited. Common Stock, Shares Outstanding, Ending Balance Shareholders' Equity, Ending Balance Allowance for Loan Losses Rollforward Analysis Allowance for Credit Losses on Financing Receivables [Table Text Block] Schedule of Allowance for Loan Loss by Segment & Impairment Methodology Schedule of Allowance for Loan Losses by Segent & Impairment Methodology [Table Text Block] Tabular disclosure of loans receivable and associated allowance for loan loss by portfolio segment and disaggregated on the basis of impairment methodology. Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Mortgage Loans Held for Sale [Member] Mortgage Loans Held for Sale [Member] Mortgage Loans Held for Sale [Member] Mortgage loans held for sale, amortized cost Loans Receivable Held-for-sale, Amount Mortgage loans held for sale, difference between fair value and amortized cost Mortgage Loans Held for Sale Difference between Fair Value and Principal Amount The difference between the fair value and principal amount of mortgage loans held for sale. Change in fair value under fair value option election Fair Value, Option, Changes in Fair Value, Gain (Loss) Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Maximum [Member] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] [Line Items] for Commitments and Contingencies Disclosure [Table] Operating leases rental expense Operating Leases, Rent Expense, Net Lease expiration period Lease Expiration Period Lease Expiration Period Lease expiration period, renewal option Lease Expiration Period, Renewal Option Lease Expiration Period, Renewal Option Income Statement [Abstract] Interest income: Interest and Dividend Income, Operating [Abstract] Interest and fees on loans Interest and Fee Income, Loans and Leases Taxable interest on securities Interest Income, Securities, Operating, Taxable Nontaxable interest on securities Interest Income, Securities, Operating, Tax Exempt Dividends on Federal Home Loan Bank stock Dividends on corporate stock and Federal Home Loan Bank stock Dividend income on corporate stock and Federal Home Loan Bank stock. Other interest income Other Interest and Dividend Income Total interest and dividend income Interest and Dividend Income, Operating Interest expense: Interest Expense [Abstract] Deposits Interest Expense, Deposits Federal Home Loan Bank advances Interest Expense Federal Home Loan Bank advances Interest expense incurred during the reporting period on short-term and long-term borrowings associated with Federal Home Loan Bank and Federal Reserve Bank advances. Junior subordinated debentures Interest Expense, Junior Subordinated Debentures Other interest expense 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] Wealth management revenues Investment Advisory, Management and Administrative Fees Mortgage banking revenues Fees and Commissions, Mortgage Banking and Servicing Service charges on deposit accounts Fees and Commissions, Depositor Accounts Card interchange fees Card interchange fees Fees earned from debit card transactions. Income from bank-owned life insurance Bank Owned Life Insurance Income Loan related derivative income Gain (Loss) on Derivative Instruments, Net, Pretax Other income Noninterest Income, Other Total noninterest income Noninterest Income Noninterest expense: Noninterest Expense [Abstract] Salaries and employee benefits Labor and Related Expense Outsourced services Outsourced services The total amount of third party vendor costs, which includes platform and product support costs. Net occupancy Occupancy, Net Equipment Equipment Expense Legal, audit and professional fees Professional Fees FDIC deposit insurance costs Federal Deposit Insurance Corporation Premium Expense Advertising and promotion Marketing and Advertising Expense Amortization of intangibles Amortization of Intangible Assets Change in fair value of contingent consideration Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Other expenses Other Noninterest Expense Total noninterest expense Noninterest Expense Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Weighted average common shares outstanding - diluted Per share information: Cash dividends declared per share Common Stock, Dividends, Per Share, Declared Risk participation-out agreement [Member] Risk participation-out agreement [Member] Risk participation agreement [Member] - Represents the agreement the Corporation has with another bank participating in a commercial loan arrangement and the participating bank guarantees the performance on a borrower-related interest rate swap contract. Number of instruments held Derivative, Number of Instruments Held Interest rate cap interest rate Derivative, Cap Interest Rate Interest rate floor interest rate Derivative, Floor Interest Rate Amount of ineffectiveness recorded in earnings Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net Cash and Cash Equivalents [Abstract] Cash and Due from Banks Cash and Cash Equivalents Disclosure [Text Block] Fair Value of Derivatives by Balance Sheet Location Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Derivative Instruments Effect in Statements of Income and Changes in Shareholders' Equity Derivative Instruments, Gain (Loss) [Table Text Block] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Troubled debt restructuring, pre-modification recorded investment Financing Receivable, Modifications, Pre-Modification Recorded Investment Troubled debt restructuring, post-modification recorded investment Financing Receivable, Modifications, Post-Modification Recorded Investment Schedule of Financing Receivables Past Due [Table] 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 Financing Receivables, 30 to 59 Days Past Due [Member] 60-89 Financing Receivables, 60 to 89 Days Past Due [Member] Over 90 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 loans Recently Issued Accounting Pronouncements Description of New Accounting Pronouncements Not yet Adopted [Text Block] Disaggregation of Revenue [Abstract] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Revenue from Contracts with Customers [Member] Revenue from Contract with Customer [Member] Net interest income Asset-based wealth management revenues Asset-based wealth management revenues Asset-based revenues include trust and investment management fees that are earned based upon a percentage of asset values under administration Transaction-based wealth management revenues Transaction-based wealth management revenues Transaction-based revenues include financial planning fees, tax preparation fees, commissions and other service fees. Total noninterest income Total revenues Revenues Debt Disclosure [Abstract] Schedule of Federal Home Loan Bank Advances, by Branch of FHLBB Bank [Table] Schedule of Federal Home Loan Bank Advances, by Branch of FHLB Bank [Table] Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Domain] Federal Home Loan Bank Branch [Domain] Federal Home Loan Bank of Boston [Member] Federal Home Loan Bank of Boston [Member] Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items] Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] Scheduled maturity through the end of the current year Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months Weighted average rate for scheduled maturity through the end of the current year Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate of Amounts Due within One Year of Balance Sheet Date Scheduled maturity in year two Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Two Weighted average rate for scheduled maturity in year two Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, One to Two Years from Balance Sheet Date Scheduled maturity in year three Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Three Weighted average rate for scheduled maturity in year three Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Two to Three Years from Balance Sheet Date Scheduled maturity in year four Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Four Weighted average rate for scheduled maturity in year four Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Three to Four Years from Balance Sheet Date Scheduled maturity in year five Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Five Weighted average rate for scheduled maturity in year five Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Four to Five Years from Balance Sheet Date Scheduled maturity after year five Federal Home Loan Bank, Advances, Maturities Summary, Due after Year Five Weighted average rate for scheduled maturity after year five Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, after Five Years from Balance Sheet Date Federal Home Loan Bank advances Total weighted average rate Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Total Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Total Regulatory Capital Requirements [Abstract] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Corporation [Member] Parent Company [Member] Bank [Member] Subsidiaries [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Total Capital (to Risk-Weighted Assets): Capital [Abstract] Total Capital Capital Total Capital to Risk-Weighted Assets Capital to Risk Weighted Assets Total Capital for Capital Adequacy Purposes Capital Required for Capital Adequacy Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets Capital Required for Capital Adequacy to Risk Weighted Assets Total Capital To Be Well Capitalized Capital Required to be Well Capitalized Total Capital To Be Well Capitalized to Risk Weighted-Assets Capital Required to be Well Capitalized to Risk Weighted Assets Tier 1 Capital (to Risk-Weighted Assets): Tier One Risk Based Capital [Abstract] Tier 1 Capital Tier One Risk Based Capital Tier 1 Capital to Risk Weighted-Assets Tier One Risk Based Capital to Risk Weighted Assets Tier 1 Capital Required For Capital Adequacy Purposes Tier One Risk Based Capital Required for Capital Adequacy Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Tier 1 Capital Required To Be Well Capitalized Tier One Risk Based Capital Required to be Well Capitalized Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Common Equity Tier 1 Capital [Abstract] Common Equity Tier 1 Capital [Abstract] Common Equity Tier 1 Capital [Abstract] Common Equity Tier 1 Capital Common Equity Tier 1 Capital Common Equity Tier 1 Capital Common Equity Tier 1 Capital to Risk Weighted Assets Common Equity Tier 1 Capital to Risk Weighted Assets Common Equity Tier 1 Capital to Risk Weighted Assets Common Equity Tier 1 Capital Required for Capital Adequacy Common Equity Tier 1 Required for Capital Adequacy Common Equity Tier 1 Required for Capital Adequacy Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets Common Equity Tier 1 Capital Required to be Well Capitalized Common Equity Tier 1 Capital Required to be Well Capitalized Common Equity Tier 1 Capital Required to be Well Capitalized Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets Tier 1 Capital (to Average Assets): Tier One Leverage Capital [Abstract] Tier 1 Leverage Capital Tier One Leverage Capital Tier 1 Leverage Capital to Average Assets Tier One Leverage Capital to Average Assets Tier 1 Leverage Capital Required for Capital Adequacy Purposes Tier One Leverage Capital Required for Capital Adequacy Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets Tier One Leverage Capital Required for Capital Adequacy to Average Assets Tier 1 Leverage Capital Required To Be Well Capitalized Tier One Leverage Capital Required to be Well Capitalized Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets Tier One Leverage Capital Required to be Well Capitalized to Average Assets Receivables from contracts with customers Contract with Customer, Asset, Net Regulatory Capital Requirements Regulatory Capital Requirements under Banking Regulations [Text Block] Segment Reporting [Abstract] Statement of Operations and Total Assets by Reportable Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Contingent Consideration by Type [Axis] Contingent Consideration by Type [Axis] Contingent Consideration Type [Domain] Contingent Consideration Type [Domain] Contingent Consideration [Member] Contingent Consideration [Member] Contingent Consideration [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance at beginning of period Payments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Balance at end of period Organization, Consolidation and Presentation of Financial Statements [Abstract] General Information Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash flows from 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] Provision for loan losses Depreciation of premises and equipment Depreciation, Nonproduction Net amortization of premium and discount Amortization of Debt Discount (Premium) Amortization of intangibles Goodwill impairment Goodwill, Impairment Loss Share-based compensation Share-based Compensation Tax benefit from stock option exercises and other equity awards Tax Benefit from Stock Option Exercises and Issuance of Other Compensation-related Equity Instruments Reductions in the entity's income taxes that arise when compensation cost (from stock option and other equity instruments compensation) recognized on the entity's tax return exceeds compensation cost from share-based compensation recognized in financial statements. This element represents the cash inflow reported in the enterprise's financing activities. Income from bank-owned life insurance Net gains on loan sales and commissions on loans originated for others, including fair value adjustments Gain (Loss) on Sales of Loans, Net Proceeds from sales of loans Proceeds from Sale of Loans Held-for-sale Loans originated for sale Payments for Origination of Mortgage Loans Held-for-sale Change in fair value of contingent consideration liability (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of mortgage-backed securities available for sale Payments to Acquire Mortgage Backed Securities (MBS) categorized as Available-for-sale Purchases of other investment securities available for sale Payments to Acquire Available-for-sale Securities Maturities and principal payments of mortgage-backed securities available for sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Maturities and principal payments of other investment securities available for sale Proceeds from Maturities, Prepayments and Calls of Other Investments Maturities and principal payments of mortgage-backed securities held to maturity Proceeds from Maturities, Prepayments and Calls of Mortgage Backed Securities (MBS) Remittance (purchases) of Federal Home Loan Bank stock Payments for (Proceeds from) Federal Home Loan Bank Stock Net (increase) decrease in loans Payments for (Proceeds from) Loans and Leases Purchases of loans Payments to Acquire Loans Held-for-investment Proceeds from the sale of property acquired through foreclosure or repossession Proceeds from Sale of Foreclosed Assets Purchases of premises and equipment Payments to Acquire Property, Plant, and Equipment Purchases of bank-owned life insurance Payment to Acquire Life Insurance Policy, Investing Activities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Net increase (decrease) in deposits Increase (Decrease) in Deposits Proceeds from Federal Home Loan Bank advances Proceeds from Federal Home Loan Bank Borrowings Repayment of Federal Home Loan Bank advances Repayments of Federal Home Loan Bank Borrowings Payment for contingent consideration liability Payment for Contingent Consideration Liability, Financing Activities Net proceeds from stock option exercises and issuance of other equity awards Proceeds from Issuance or Sale of Equity Cash dividends paid Payments of Dividends 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 at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Noncash Investing and Financing Activities: Noncash Investing and Financing Items [Abstract] Loans charged off Financing Receivable, Allowance for Credit Losses, Write-downs Loans transferred to property acquired through foreclosure or repossession Transfer of Loans Net to Foreclosed Properties and Repossessions Transfer of Loans Net to Foreclosed Properties and Repossessions Supplemental Disclosures: Supplemental Cash Flow Information [Abstract] Interest payments Interest Paid Income tax payments Income Taxes Paid Components of Net Periodic Benefit Cost Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Assumptions Used for Net Periodic Benefit Cost Schedule of Assumptions Used [Table Text Block] Business Segments Segment Reporting Disclosure [Text Block] Fair Value Inputs, Assets, Quantitative Information [Table] Fair Value Inputs, Assets, Quantitative Information [Table] Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Weighted Average [Member] Weighted Average [Member] Collateral Dependent Impaired Loans [Member] Collateral Dependent Impaired Loans [Member] The represents collateral dependent impaired loans. Property Acquired Through Foreclosure Or Repossession [Member] Property Acquired Through Foreclosure Or Repossession [Member] This represents property acquired through foreclosure or repossession. Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Appraisals Of Collateral [Member] Appraisals Of Collateral [Member] This represent appraisals of collateral valuation techinque used in fair value disclosures. Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Line Items] Collateral dependent impaired loans Property acquired through foreclosure or repossession Other Real Estate, Foreclosed Assets, and Repossessed Assets Discount for costs to sell Discount For Costs To Sell This represents the discount applied to appraisals of collateral for costs to sell. Appraisal adjustments Appraisal Adjustments This represents the adjustments to appraisal values to reflect market value declines or other discounts. Borrowings Debt Disclosure [Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Number of securities in a continuous unrealized loss position for less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Number This item represents the number of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Fair value of securities in a continuous unrealized loss position for less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Unrealized losses of securities in a continuous unrealized loss position for less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Accumulated Investments Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Accumulated Investments Number of securities in a continuous unrealized loss position for 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Number This item represents the number of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Fair value of securities in a continuous unrealized loss position for 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss, Accumulated Investments Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss, Accumulated Investments Fair value of securities in a continuous unrealized loss position total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Unrealized losses of securities in a continuous unrealized loss position total Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Summary of Investments Unrealized Gain (Loss) on Investments [Table Text Block] Securities by Contractual Maturity Investments Classified by Contractual Maturity Date [Table Text Block] Securities in a Continuous Unrealized Loss Position Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Consolidation Consolidation, Policy [Policy Text Block] Basis of Accounting Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recorded investment in Troubled Debt Restructuring, Recorded Investment Financing Receivable, Modifications, Recorded Investment Specific Reserves on Troubled Debt Restructurings Specific Reserves on Troubled Debt Restructurings The amount of specific reserves on troubled debt restructurings. Balance Sheet Offsetting Balance Sheet Offsetting [Table Text Block] Tabular disclosure of derivative assets and derivative liabilities that are subject to offsetting, including master netting arrangements. Loan related derivative income [Member] Net Gains Losses on Interest Rate Swaps [Member] This amount represents net gains (losses) on interest rate swaps. Mortgage banking revenues [Member] Net Gains on Loan Sales and Commissions on Loans Originated for Others [Member] This amount is included in net gains on loan sales and commissions on loans originated for others. Gain (Loss) Recognized in Income Derivative, Gain (Loss) on Derivative, Net Unused line of credit with FHLBB Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds Unused remaining available borrowing capacity with FHLBB Line of Credit Facility, Remaining Borrowing Capacity Retirement Benefits [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Equivalent single discount rate for benefit obligations Equivalent single discount rate for benefit obligations The interest rate used to adjust for the time value of money in the calculation of the defined benefit obligation. Equivalent single discount rate for service cost The interest rate used to adjust for the time value of money in the calculation of the service cost component of net periodic benefit cost. Equivalent single discount rate for interest cost Equivalent single discount rate for interest cost The interest rate used to adjust for the time value of money in the calculation of the interest cost component of net periodic benefit cost. Expected long-term return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Balance Sheet Offsetting Balance Sheet Offsetting [Text Block] The entire disclosure for derivative assets and derivative liabilities that are subject to offsetting, including master netting arrangements, and are offset in the consolidated balance sheets. Leases [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Acquisition [Abstract] Acquisition [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due Through End of Current Year Operating Leases, Future Minimum Payments Due, Next Twelve Months Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Three Years Operating Leases, Future Minimum Payments, Due in Three Years Operating Leases, Future Minimum Payments, Due in Four Years Operating Leases, Future Minimum Payments, Due in Four Years Operating Leases, Future Minimum Payments, Due in Five Years Operating Leases, Future Minimum Payments, Due in Five Years Operating Leases, Future Minimum Payments, Due Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Self-originated Mortgages Self-originated Mortgages [Member] Self-originated Mortgages [Member] Purchased Mortgages Purchased Mortgages [Member] Purchased Mortgages [Member] Total assets at fair value on a nonrecurring basis Assets, Fair Value Disclosure, Nonrecurring Available for sale securities amortized cost basis Available-for-sale Securities, Amortized Cost Basis Available for sale securities unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Available for sale securities unrealized losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Held to maturity securities unrealized gains Held-to-maturity Securities, Accumulated Unrecognized Holding Gain Held to maturity securities unrealized losses Held-to-maturity Securities, Accumulated Unrecognized Holding Loss Held to maturity securities fair value Total available for sale and held to maturity securities amortized cost Available for Sale and Held to Maturity Securities Amortized Cost This represents the total available for sale and held to maturity securities amortized cost. Total available for sale and held to maturity securities unrealized gains Available for Sale and Held to Maturity Securities Accumulated Unrecognized Holding Gain This represents the total available for sale and held to maturity securities unrealized gains. Total available for sale and held to maturity securities unrealized losses Available for Sale and Held to Maturity Securities Accumulated Unrecognized Holding Loss This represents the total available for sale and held to maturity securities unrealized losses. Total available for sale and held to maturity securities fair value Available for Sale and Held to Maturity Securities Fair Value This represents the total available for sale and held to maturity securities fair value. Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Transferred at Point in Time [Member] Transferred at Point in Time [Member] Transferred over Time [Member] Transferred over Time [Member] Total revenues Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Commercial Banking [Member] Commercial Banking [Member] The represents the commercial banking reporting segment. Wealth Management Services [Member] Wealth Management Services [Member] This represents the wealth management services reporting segment. Corporate [Member] Corporate Segment [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Net interest income (expense) Noninterest income Depreciation and amortization expense Depreciation, Depletion and Amortization Other noninterest expenses related to segments Other Noninterest Expenses Related to Segments Other noninterest expenses related to segments. Total assets Expenditures for long-lived assets Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Average Recorded Investment of Impaired Loans Impaired Financing Receivable, Average Recorded Investment Interest Income Recognized on Impaired Loans Impaired Financing Receivable, Interest Income, Cash Basis Method Fair Value Measurements Fair Value Disclosures [Text Block] Securities held to maturity, fair value Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Earn-out period post acquisition Earn-out period post acquisition The period of time in which contingent consideration as a result of the acquisition can be earned. Allowance For Loan Loss Allocation on Collateral Dependent Impaired Loans Allowance For Loan Loss Allocation on Collateral Dependent Impaired Loans The allowance for loan loss allocation on collateral dependent impaired loans. Payment of contingent consideration liability Other Consumer [Member] Other Consumer [Member] Fixed-rate consumer installment loans. Nonaccrual Loans, Current Payment Status [Axis] Nonaccrual Loans, Current Payment Status [Axis] Loans on nonaccrual status which are current as to payment of principal and interest. Current Payment Status [Domain] Nonaccrual Loans, Current Payment Status [Domain] Nonaccrual loans which are current as to payment of principal and interest [Domain] Current Payment Status [Member] Current Payment Status [Member] Current Payment Status [Member] Nonaccrual loans Financing Receivable, Recorded Investment, Nonaccrual Status Accruing loans 90 days or more past due Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Nonaccrual loans current on payment Loans Receivable, Nonaccrual of Interest, Current Reflects carrying amount of loans on which no interest is being recognized, but are current as to the payment of principal and interest. Revenue from Contracts with Customers Revenue Recognition, Sales of Services [Policy Text Block] Financing Receivable Information by Portfolio Segment [Axis] Financing Receivable Allowance [Domain] Financing Receivable, Allowance for Credit Losses [Roll Forward] Financing Receivable, Allowance for Credit Losses [Roll Forward] Allowance, Beginning Balance Charge-offs Recoveries Financing Receivable, Allowance for Credit Losses, Recovery Provision Provision for Loan, Lease, and Other Losses Allowance, Ending Balance Regulatory Capital Requirements Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Calculation of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Earnings Per Common Share Earnings Per Share [Text Block] 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 Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] 2018 Grant [Member] 2018 Grant [Member] 2018 Grant [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Performance Based Nonvested Shares [Member] Performance Based Nonvested Shares [Member] Performance based nonvested shares. Time Based Nonvested Shares [Member] Time Based Nonvested Shares [Member] Time based nonvested shares. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Performance share awards, grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in the Period, Grant Date Fair Value The fair value at date of grant for nonvested performance equity based awards during the period. Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Performance share awards, minimum target percentage Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Shares Earned to Target Percentage, Minimum Percent of shares earned to the target for equity instruments other than options, the minimum percentage of the range. Performance share awards, maximum target percentage Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Shares Earned to Target Percentage, Maximum Percent of shares earned to the target of equity instruments other than options, the maximum percentage of the range. Performance share awards, shares vesting percentage Share-based Compensation Arrangement by Share-based Award, Equity Instruments Other than Options, Shares Vesting Percentage The current assumption based on the most recent information available shares vesting percentage for performance nonvested equitybased awards. Performance share awards, shares vesting Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Shares Vesting Shares vesting for performance nonvested equity based awards based on the most recent information available. Nonvested share units granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Nonvested share units weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Document and Entity Information [Abstract] Document and Entity 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 Activity in Other Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Components of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Average reserve deposited with the Board of Governors of the Federal Reserve Bank Cash Reserve Deposited At Federal Reserve Bank Average reserve balance reqired to be maintained at the Federal Reserve Bank. Interest-bearing deposits in other banks Interest-bearing Deposits in Banks and Other Financial Institutions Defined Benefit Pension Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Federal Home Loan Bank Advances Maturities Schedule of Federal Home Loan Bank, Advances, by Branch of FHLB Bank [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Transition Period Pension Plan Amendment Transition Period Pension Plan Amendment The period in which pension plans amendments will transition. Available-for-sale Securities and Other Short-term Investments, Rabbi Trusts Available-for-sale Securities and Other Short-term Investments, Rabbi Trusts Available-for-sale Securities and Other Short-term Investments, Rabbi Trusts