Earnings Per Share [Abstract] Net Income Per Common Share Earnings Per Share [Text Block] Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] FCB Financial Holdings, Inc. FCB Financial Holdings, Inc. [Member] FCB Financial Holdings, Inc. [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Synovus common stock issued and reissued from treasury attributed to purchase price Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Cash payments to FCB stockholders attributed to purchase price Payments To Acquire Business Gross, Excluding Share Based Awards Payments To Acquire Business Gross, Excluding Share Based Awards Fair value of exchanged employee and director equity awards and FCB warrants attributed to purchase price Business Combination, Consideration Transferred, Other Equity Awards Business Combination, Consideration Transferred, Other Equity Awards Total purchase price Business Combination, Consideration Transferred Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Investment securities available for sale Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities Loans Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Cash surrender value of bank-owned life insurance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash Surrender Value of Bank-owned Life Insurance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash Surrender Value of Bank-owned Life Insurance Premises and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Core deposit intangible Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Total Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits Federal funds purchased and securities sold under repurchase agreements Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Federal Funds Purchased and Securities Sold Under Repurchase Agreements Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Federal Funds Purchased and Securities Sold Under Repurchase Agreements Long-term debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Total Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Fair value of net identifiable assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Preliminary goodwill Goodwill Closing stock price (in dollars per share) Share Price Cash paid Payments to Acquire Businesses, Gross Statement of Comprehensive Income [Abstract] Net income, Before-tax Amount Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Net income, Tax Effect Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Net unrealized gains (losses) on investment securities available for sale: Before-tax Amount Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract] Reclassification adjustment for net losses realized in net income, Before-tax Amount Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Net unrealized gains (losses) arising during the period, Before-tax Amount Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Net unrealized gains (losses), Before-tax Amount Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax Net unrealized gains on investment securities available for sale: Tax Effect Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax [Abstract] Reclassification adjustment for net losses realized in net income, Tax Effect Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Net unrealized gains (losses) arising during the period, Tax Effect Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax Net unrealized gains (losses), Tax Effect Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax Net unrealized gains on investment securities available for sale: Net of Tax Amount Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract] Reclassification adjustment for net losses realized in net income, Net of Tax Amount Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Net unrealized gains (losses) arising during the period, Net of Tax Amount Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Net unrealized gains (losses), Net of Tax Amount Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Post-retirement unfunded health benefit: Before-tax Amount Amortization of Post-retirement Unfunded Health Benefit Before Tax Amount [Abstract] Amortization of Post-retirement Unfunded Health Benefit Before Tax Amount [Abstract] Reclassification adjustment for gains realized in net income, Before-tax Amount Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax Post-retirement unfunded health benefit: Tax Effect Amortization of Post-retirement Unfunded Health Benefit, Tax (Expense) Benefit [Abstract] Amortization of Post-retirement Unfunded Health Benefit, Tax (Expense) Benefit [Abstract] Reclassification adjustment for gains realized in net income, Tax Effect Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Post-retirement unfunded health benefit: Net of Tax Amount Amortization of Post-retirement Unfunded Health Benefit, Net of Tax [Abstract] Amortization of Post-retirement Unfunded Health Benefit, Net of Tax [Abstract] Reclassification adjustment for gains realized in net income, Net of Tax Amount Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax Other comprehensive income (loss), Before-tax Amount Other Comprehensive Income (Loss), before Tax Other comprehensive income (loss), Tax Effect Other Comprehensive Income (Loss), Tax Other comprehensive income (loss), Net of Tax Amount Other Comprehensive Income (Loss), Net of Tax Comprehensive income, Net of Tax Amount Comprehensive Income (Loss), Net of Tax, Attributable to Parent Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Stock issued in acquisitions (in shares) Stock Issued During Period, Shares, Acquisitions Treasury stock reissued (in shares) Stock Issued During Period, Shares, Treasury Stock Reissued Payments of stock issuance costs Payments of Stock Issuance Costs Merger exchange ratio Business Combination, Common Stock, Shares Outstanding, Merger Exchange Ratio Business Combination, Common Stock, Shares Outstanding, Merger Exchange Ratio Consideration transferred Authorized amount Stock Repurchase Program, Authorized Amount Value repurchased Stock Repurchased During Period, Value Shares repurchased (in shares) Treasury Stock, Shares, Acquired Shares repurchased, average cost per share (in dollars per share) Treasury Stock Acquired, Average Cost Per Share Acquisitions Business Combination Disclosure [Text Block] Investments [Abstract] Proceeds from sales of investment securities available for sale Proceeds from Sale of Debt Securities, Available-for-sale Gross realized gains on sales Debt Securities, Available-for-sale, Realized Gain Gross realized losses on sales Debt Securities, Available-for-sale, Realized Loss Investment securities losses, net Debt Securities, Available-for-sale, Realized Gain (Loss) Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Reporting Unit [Axis] Reporting Unit [Axis] Reporting Unit [Domain] Reporting Unit [Domain] Synovus Bank Reporting Unit Synovus Bank [Member] Synovus Bank [Member] Trust Services Reporting Unit Trust Services [Member] Trust Services [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill [Roll Forward] Goodwill [Roll Forward] Balance as of December 31, 2018 Goodwill acquired during the year (preliminary allocation) and adjustments Goodwill, Acquired During Period Balance as of June 30, 2019 Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Investment Securities Available for Sale Available-for-sale Securities [Member] Private Equity Investments Private Equity Funds [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] GGL / SBA Loans Servicing Asset SBA/GGL Servicing Asset [Member] SBA /GGL Servicing Asset [Member] Earnout Liability Other Liabilities [Member] Visa Derivative Other Derivative Liability Contracts [Member] Other Derivative Liability Contract [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Losses included in earnings attributable to the change in unrealized losses relating to assets/liabilities Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Included in earnings Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Unrealized gains (losses) included in OCI Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss) Additions Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Additions Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Additions Settlements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Ending balance Total net losses for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease), Included in Earnings Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease), Included in Earnings Commitments and Contingencies Disclosure [Abstract] Loan Commitments and Letters of Credit Loan Commitments and Letters of Credit [Table Text Block] Loan Commitments and Letters of Credit [Table Text Block] Leases [Abstract] Assets And Liabilities, Lessee Assets And Liabilities, Lessee [Table Text Block] Assets And Liabilities, Lessee [Table Text Block] Lease, Cost Lease, Cost [Table Text Block] Lease Term and Discount Rate, Lessee Lease Term and Discount Rate, Lessee [Table Text Block] Lease Term and Discount Rate, Lessee [Table Text Block] Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Finance Lease, Liability, Maturity Finance Lease, Liability, Maturity [Table Text Block] Schedule of Business Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Schedule of Acquisition Related Costs Schedule of Business Acquisition, Acquisition Related Costs [Table Text Block] Schedule of Business Acquisition, Acquisition Related Costs [Table Text Block] Loans and Allowance for Loan Losses [Abstract] Loans and Allowance for Loan Losses [Abstract] Financing Receivable, Troubled Debt Restructuring [Table] Financing Receivable, Troubled Debt Restructuring [Table] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Below Market Interest Rate Interest Rate Below Market Reduction [Member] Other Concessions Term Extensions and or Other Concessions [Member] Term Extensions and/or Other Concessions [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Total commercial and industrial Commercial And Industrial [Member] Commercial and Industrial [Member] Total commercial real estate Commercial Real Estate [Member] Total consumer Retail [Member] Financing Receivable, Recorded Investment, by Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Financing Receivable, Recorded Investment, Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Commercial, financial and agricultural Commercial, Financial and Agricultural [Member] Commercial, Financial and Agricultural [Member] Owner-occupied Owner-Occupied [Member] Owner-Occupied [Member] Investment properties Investment Properties [Member] Investment Properties [Member] 1-4 family properties One To Four Family Properties [Member] One To Four Family Properties [Member] Land and development Land Acquisition [Member] Land Acquisition [Member] Consumer mortgages Consumer Loan [Member] Home equity lines Home Equity Line of Credit [Member] Other consumer loans Other Consumer Loans [Member] Other Consumer Loans [Member] Financing Receivable, Troubled Debt Restructuring [Line Items] Financing Receivable, Troubled Debt Restructuring [Line Items] Number of Contracts Financing Receivable, Modifications, Number of Contracts Recorded Investment Financing Receivable, Troubled Debt Restructuring, Postmodification Net charge-offs Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Measurements, Nonrecurring Basis Fair Value, Nonrecurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [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] Other assets held for sale Other Assets [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] Impaired loans Impaired Financing Receivable, Recorded Investment Other loans held for sale Loans Receivable Held-for-sale, Amount Other real estate Real Estate Acquired Through Foreclosure Other assets held for sale Other Assets, Fair Value Disclosure Global One Global One [Member] Global One [Member] Title of Individual [Axis] Title of Individual [Axis] Title of Individual [Domain] Title of Individual [Domain] Executives Executives [Member] Executives [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Identifiable assets acquired Service banking centers acquired Service Banking Centers Acquired Service Banking Centers Acquired Other equity compensation, non-vested shares outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Cash equivalents Merger Exchange, Cash Equivalents Merger Exchange, Cash Equivalents Synovus common stock issued and reissued from treasury Converted options and restricted share units, fair value Share-based Compensation Arrangement by Share-based Payment Award, Converted Awards, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Converted Awards, Fair Value Share based awards allocated to purchase price Share-based Compensation Arrangement by Share-based Payment Award, Converted Awards, Purchase Price Allocation Share-based Compensation Arrangement by Share-based Payment Award, Converted Awards, Purchase Price Allocation Warrants converted fair value Warrants Converted Fair Value Warrants Converted Fair Value Goodwill Merger-related expense Business Combination, Acquisition Related Costs Core deposits decrease Finite-Lived Core Deposits Increase (Decrease), Gross Finite-Lived Core Deposits Increase (Decrease), Gross Estimated useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Period of additional annual payments Period of Additional Annual Payments Period of Additional Annual Payments Increase in earnout liabilities Increase (Decrease) in Earnout Liabilities Increase (Decrease) in Earnout Liabilities Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock Common Stock, Value, Issued Earnout payments, cash Earnout Payments, Cash Earnout Payments, Cash Earnout liability Earnout Liability Earnout Liability Amortization of intangibles Amortization of Intangible Assets Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Core Deposits Core Deposits [Member] Core deposits Finite-Lived Core Deposits, Gross Useful life Finite-Lived Intangible Asset, Useful Life Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Unpaid Principal Balance Impaired Financing Receivable, Unpaid Principal Balance Recorded Investment, Without an ALL Impaired Financing Receivable, with No Related Allowance, Recorded Investment Recorded Investment, With an ALL Impaired Financing Receivable, with Related Allowance, Recorded Investment Related Allowance Impaired Financing Receivable, Related Allowance Average Recorded Investment Impaired Financing Receivable, Average Recorded Investment Interest Income Recognized Impaired Financing Receivable, Interest Income, Accrual Method Interest income, cash basis method Impaired Financing Receivable, Interest Income, Cash Basis Method Subsequent Events [Abstract] Subsequent Event Subsequent Events [Text Block] Investment Securities Available for Sale Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Basic Net Income Per Common Share: Earnings Per Share, Basic [Abstract] Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Net income per common share, basic (in dollars per share) Earnings Per Share, Basic Diluted Net Income Per Common Share: Earnings Per Share, Diluted [Abstract] Effect of dilutive outstanding equity-based awards, warrants, and earnout payments Potentially Dilutive Shares from Assumed Exercise of Securities or Other Contracts to Purchase Common Stock Potentially Dilutive Shares from Assumed Exercise of Securities or Other Contracts to Purchase Common Stock Weighted average number of diluted common shares (in shares) Weighted Average Number of Shares Outstanding, Diluted Net income per common share, diluted (in dollars per share) Earnings Per Share, Diluted Statement of Financial Position [Abstract] Preferred Stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred Stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding 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 outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock, shares at cost (in shares) Treasury Stock, Shares Summary of Available-for-Sale Investment Securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of Unrealized Loss on Investments Schedule of Unrealized Loss on Investments [Table Text Block] Amortized Cost and Estimated Fair Value by Contractual Maturity of Investment Securities Available-for-Sale Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Activity for Available-for-Sale Securities Realized Gain (Loss) on Investments [Table Text Block] ASSETS Assets [Abstract] Cash and due from banks Cash and Due from Banks Interest-bearing funds with Federal Reserve Bank Interest bearing funds with Federal Reserve Bank Interest bearing funds deposited with the Federal Reserve Bank. Interest earning deposits with banks Interest-bearing Deposits in Banks and Other Financial Institutions Federal funds sold and securities purchased under resale agreements Federal Funds Sold and Securities Purchased under Agreements to Resell Total cash, cash equivalents, restricted cash, and restricted cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Investment securities available for sale, at fair value Debt Securities, Available-for-sale Mortgage loans held for sale, at fair value Mortgages Held-for-sale, Fair Value Disclosure Loans Loans and Leases Receivable, Net of Deferred Income Allowance for loan losses Loans and Leases Receivable, Allowance Loans, net Loans and Leases Receivable, Net Amount Cash surrender value of bank-owned life insurance Bank Owned Life Insurance Premises and equipment, net Property, Plant and Equipment, Net Other intangible assets Other Intangible Assets, Net Other assets Other Assets Total assets Assets LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity [Abstract] Liabilities Liabilities [Abstract] Deposits: Deposits [Abstract] Non-interest-bearing deposits Noninterest-bearing Deposit Liabilities Interest-bearing deposits Interest-Bearing Deposit Liabilities And Time Deposits Interest-Bearing Deposit Liabilities And Time Deposits Total deposits Deposits Federal funds purchased and securities sold under repurchase agreements Federal Funds Purchased And Other Short Term Borrowings Federal funds purchased, repurchase agreements, and other short-term borrowings Other short-term borrowings Other Short-term Borrowings Long-term debt Long-term Debt Other liabilities Other Liabilities Total liabilities Liabilities Shareholders' Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Series D Preferred Stock – no par value. Authorized 100,000,000 shares; 8,000,000 shares issued and outstanding at June 30, 2019 and December 31, 2018 Preferred Stock, Value, Issued Common stock - $1.00 par value. Authorized 342,857,143 shares; 166,079,543 issued at June 30, 2019 and 143,300,449 issued at December 31, 2018; 156,872,026 outstanding at June 30, 2019 and 115,865,510 outstanding at December 31, 2018 Additional paid-in capital Additional Paid in Capital Treasury stock, at cost – 9,207,517 shares at June 30, 2019 and 27,434,939 shares at December 31, 2018 Treasury Stock, Value Accumulated other comprehensive income (loss), net Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total shareholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders' equity Liabilities and Equity Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series E Preferred Stock Series E Preferred Stock [Member] Triggering Events [Axis] Triggering Events [Axis] Triggering Events [Axis] Triggering Events [Domain] Triggering Events [Domain] [Domain] for Triggering Events [Axis] Until July 1, 2024 (Excluding July 1, 2024) Until July 1, 2024 (Excluding July 1, 2024) [Member] Until July 1, 2024 (Excluding July 1, 2024) [Member] From July 1, 2024 (Including July 1, 2024) From July 1, 2024 (Including July 1, 2024) [Member] From July 1, 2024 (Including July 1, 2024) [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Face amount Debt Instrument, Face Amount Proceeds from issuance of debt Proceeds from Issuance of Debt Preferred stock, dividend rate, percentage Preferred Stock, Dividend Rate, Percentage Redemption period from regulatory capital treatment Sale of Stock, Redemption Period from Regulatory Capital Treatment Sale of Stock, Redemption Period from Regulatory Capital Treatment Preferred stock, redemption price per share (in usd per share) Preferred Stock, Redemption Price Per Share Accounting Policies [Abstract] Number of branches Number of Branches Number of Branches Number of ATMs Number of ATMs Number of ATMs Operating lease, right-of-use asset Operating Lease, Right-of-Use Asset Operating lease, liability Operating Lease, Liability Basis Of Presentation [Table] Basis Of Presentation [Table] Basis Of Presentation [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 Accounting Standards Update 2016-02 [Member] Retained Earnings Retained Earnings [Member] Premises and Equipment Premises and Equipment [Member] Premises and Equipment [Member] Basis Of Presentation [Line Items] Basis Of Presentation [Line Items] Basis Of Presentation [Line Items] Adjustment from adoption of ASU Cumulative Effect of New Accounting Principle in Period of Adoption Assets finance Finance Lease, Right-of-Use Asset Deferred gains on sale-leaseback transactions Sale Leaseback Transaction, Deferred Gain, Net Share-based Payment Arrangement [Abstract] Share-based Compensation Share-based Payment Arrangement [Text Block] Contractually required principal and interest at acquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition Non-accretable difference (expected losses and foregone interest) Certain Loans Acquired in Transfer, Nonaccretable Difference Cash flows expected to be collected at acquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition Accretable yield Certain Loans Acquired in Transfer, Accretable Yield Basis in ASC 310-30 loans at acquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Nature of Expense [Axis] Nature of Expense [Axis] Interim Period, Costs Not Allocable [Domain] Interim Period, Costs Not Allocable [Domain] Compensation Expense and Remaining to Purchase Price Compensation Expense and Remaining to Purchase Price [Member] Compensation Expense and Remaining to Purchase Price [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Merger-related expense Merger-Related Expense [Member] Merger-Related Expense [Member] Merger-related expense, settle in equity Merger-Related Expense, Settle in Equity [Member] Merger-Related Expense, Settle in Equity [Member] Merger-related expense, settled in cash Merger-Related Expense, Settled in Cash [Member] Merger-Related Expense, Settled in Cash [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Assumed (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Assumed in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Assumed in Period Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Share-based compensation expense Share-based Payment Arrangement, Expense Summary of Derivative Instruments [Abstract] Impact of Derivatives on Balance Sheet Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Effect of Fair Value Hedges on Consolidated Statements of Income Effect of Fair Value Hedges on the Consolidated Statements of Income Effect of Fair Value Hedges on the Consolidated Statements of Income Fair Value, By Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Measurements, Recurring Basis Fair Value, Recurring [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Mortgage-backed securities issued by U.S. Government agencies Mortgage Backed Securities Issued By U S Government Agencies [Member] Mortgage Backed Securities Issued By U S Government Agencies [Member] Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises [Member] Collateralized Mortgage Obligations Issued by U.S. Government Sponsored Enterprises [Member] Other mortgage-backed securities Mortgage Backed Securities, Other [Member] Corporate debt securities Other Investments [Member] U.S. Treasury securities US Treasury Securities [Member] U.S. Government agency securities US Government Agencies Debt Securities [Member] Mortgage-backed securities issued by U.S. Government sponsored enterprises Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Commercial mortgage-backed securities issued by U.S. Government sponsored enterprises Commercial mortgage-backed securities issued by U.S. Government sponsored agencies [Member] Commercial mortgage-backed securities issued by U.S. Government sponsored agencies [Member] State and municipal securities US States and Political Subdivisions Debt Securities [Member] Asset-backed securities Asset-backed Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Mutual funds Mutual Fund [Member] Interest rate contracts Interest Rate Contract [Member] Mortgage derivatives Mortgage Derivatives [Member] Mortgage Derivatives [Member] Visa derivative Visa Derivative [Member] Visa Derivative [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Trading securities Debt Securities, Trading, and Equity Securities, FV-NI Investment securities available for sale Private equity investments Private Equity Investments Private Equity Investments Mutual funds Equity Securities, FV-NI Mutual funds held in rabbi trusts Mutual Funds Held In Rabbi Trusts Mutual funds held In Rabbi Trusts. GGL/SBA loans servicing asset Servicing Asset at Fair Value, Amount Derivative assets Derivative Asset Earnout liability Earnout Liabilities, Fair Value Disclosure Earnout Liabilities, Fair Value Disclosure Derivative liabilities Derivative Liability Statement of Cash Flows [Abstract] Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net income 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 Provision for Loan and Lease Losses Depreciation, amortization, and accretion, net Depreciation, Amortization and Accretion, Net Deferred income tax expense Deferred Income Tax Expense (Benefit) Originations of mortgage loans held for sale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from sales of mortgage loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Gain on sales of mortgage loans held for sale, net Gain (Loss) on Sale of Mortgage Loans Increase in other assets Increase (Decrease) in Prepaid Expense and Other Assets (Decrease) increase in other liabilities Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Investment securities losses, net Share-based compensation expense Share-based Payment Arrangement, Noncash Expense 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] Net cash received in business combination, net of cash paid Cash Acquired from Acquisition Proceeds from maturities and principal collections of investment securities available for sale Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Purchases of investment securities available for sale Payments to Acquire Debt Securities, Available-for-sale Proceeds from sales of loans Proceeds from Sale of Loans Held-for-investment Proceeds from sales of other real estate and other assets Proceeds from Sale of Other Real Estate Net increase in loans excluding loans acquired in business combination Payments for (Proceeds from) Loans and Leases Net (purchases) redemptions of Federal Home Loan Bank stock Payments for (Proceeds from) Federal Home Loan Bank Stock Net (purchases) redemptions of Federal Reserve Bank stock Payments for (Proceeds from) Federal Reserve Bank Stock Proceeds from settlements of bank-owned life insurance policies Purchases of Bank-owned Life Insurance Policies, Net of Settlements Purchases of Bank-owned Life Insurance Policies, Net of Settlements Net increase in premises and equipment Payments to Acquire Property, Plant, and Equipment Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Net increase in deposits Increase (Decrease) in Deposits Net increase in federal funds purchased and securities sold under repurchase agreements Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net Net change in other short-term borrowings Payments for (Proceeds from) Short-term Investments Repayments and redemption of long-term debt Repayments of Long-term Debt Proceeds from issuance of long-term debt, net Proceeds from Issuance of Long-term Debt Dividends paid to common shareholders Payments of Ordinary Dividends, Common Stock Dividends paid to preferred shareholders Payments of Ordinary Dividends, Preferred Stock and Preference Stock Proceeds from issuance of Series D Preferred Stock Proceeds from Issuance of Preferred Stock and Preference Stock Stock options and warrants exercised Proceeds from Stock Options and Warrants Exercised Proceeds from Stock Options and Warrants Exercised Repurchase of common stock Payments for Repurchase of Common Stock Taxes paid related to net share settlement of equity awards Taxes paid related to net share settlement of equity awards Taxes paid related to net share settlement of equity awards Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Increase in cash and cash equivalents including restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents, restricted cash, and restricted cash equivalents at beginning of period Cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period Supplemental Disclosures: Supplemental Cash Flow Information [Abstract] Income taxes paid (refunded) Income Taxes Paid, Net Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activities Non-cash Activities Noncash Investing and Financing Items [Abstract] Common stock issued, treasury stock reissued, equity awards/warrants exchanged to acquire FCB Stock Issued During Period, Value, Treasury Stock Reissued, Equity Awards/Warrants Converted in Acquisition Stock Issued During Period, Value, Treasury Stock Reissued, Equity Awards/Warrants Converted in Acquisition Premises and equipment transferred to other assets held for sale Premises and Equipment Transferred to/(from) Other Assets Held for Sale Premises and Equipment Transferred to/(from) Other Assets Held for Sale Loans foreclosed and transferred to other real estate Loans Foreclosed and Transferred to Other Real Estate Loans Foreclosed and Transferred to Other Real Estate Loans transferred to/(from) other loans held for sale at fair value Loans transferred to other loans held for sale at fair value Loans transferred to other loans held for sale at fair value Subtopic 825-10 equity investment securities available for sale transferred to other assets Equity investment securities available for sale transferred to other assets at fair value Equity investment securities available for sale transferred to other assets at fair value Dividends declared on common stock during the period but paid after period-end Dividends Payable Schedule of Current, Accruing Past Due, and Nonaccrual Loans Financing Receivable, Nonaccrual [Table Text Block] Loan Portfolio Credit Exposure Loan Portfolio Credit Exposure [Table Text Block] Loan Portfolio Credit Exposure [Table Text Block] Schedule of Acquired Portfolio Loans Schedule of Acquired Portfolio Loans [Table Text Block] Schedule of Acquired Portfolio Loans [Table Text Block] Schedule Of Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Movement Schedule Of Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Movement [Table Text Block] Schedule Of Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Movement [Table Text Block] Schedule of Allowances for Loan Losses and Recorded Investment in Loans Allowance for Credit Losses [Text Block] Schedule of Impaired Loans Impaired Financing Receivables [Table Text Block] Troubled Debt Restructurings Financing Receivable, Troubled Debt Restructuring [Table Text Block] Fair value Mortgage Loans Held-for-Sale [Member] Mortgage Loans Held-for-Sale [Member] Loans receivable held-for-sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Unpaid principal balance Fair value option, aggregate unpaid principal balance of mortgage loans held for sale Fair value option, aggregate unpaid principal balance of mortgage loans held for sale. Fair value less aggregate unpaid principal balance Fair Value, Option, Aggregate Differences, Long-term Debt Instruments Mortgage loans held for sale Change In Mortgage Loans Held For Sale Included In Net Income Changes in the fair value of mortgage loans held for sale that were included in the consolidated statements of income during the reporting period. Share-based Compensation, Stock Options, Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Schedule of Nonvested Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Share-based Compensation, Allocation of Recognized Period Costs Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Commercial & Industrial Commercial Real Estate Consumer Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Allowance for loan losses: Allowance for Loan and Lease Losses [Roll Forward] Beginning balance, allowance Charge-offs Allowance for Loan and Lease Losses, Write-offs Recoveries Allowance for Loan and Lease Loss, Recovery of Bad Debts Provision for (reversal of) loan losses Ending balance, allowance Ending balance: individually evaluated for impairment, allowance Financing Receivables, Allowance for Credit Losses, Individually Evaluated for Impairment Allowance for Credit Losses related to loans individually evaluated for impairment. Ending balance: collectively evaluated for impairment, allowance Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Ending balance: total loans Loans and Leases Receivable, Gross, Including Acquired Loans Loans and Leases Receivable, Gross, Including Acquired Loans Total loans Loans and Leases Receivable, Gross Ending balance: individually evaluated for impairment, loans Financing Receivable, Individually Evaluated for Impairment Ending balance: collectively evaluated for impairment, loans Financing Receivable, Collectively Evaluated for Impairment Ending balance: acquired loans accounted for under ASC 310-30 Financing Receivable, Acquired Loans Financing Receivable, Acquired Loans Allowance for purchased credit-impaired loans Allowance for Purchased Credit-impaired Loans Allowance for Purchased Credit-impaired Loans Deferred fees and costs, net Loans and Leases Receivable, Deferred Income Acquired collectively evaluated for impairment loan discount Acquired Collectively Evaluated for Impairment Loan Discount Acquired Collectively Evaluated for Impairment Loan Discount Acquired loans under 310-30 loan discount Acquired Loans Under 310-30 Loan Discount Acquired Loans Under 310-30 Loan Discount Purchased credit-impaired loans Purchased Credit-impaired Loans Purchased Credit-impaired Loans Collateral [Axis] Collateral [Axis] Collateral [Domain] Collateral [Domain] Collateral Pledged Collateral Pledged [Member] Pledged to secure deposits Debt Securities, Available-for-sale, Restricted Investment securities in a loss position for less than twelve months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions Investment securities in a loss position for twelve months or longer Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Guarantee obligations Guarantee Obligations [Member] Letters of credit Standby Letters of Credit [Member] Commitments to fund commercial and industrial loans Commitments to Fund Commercial and Industrial Loans [Member] Commitments to Fund Commercial and Industrial Loans [Member] Commitments to fund commercial real estate, construction, and land development loans Commitments to Fund Commercial Real Estate, Construction, and Land Development Loans [Member] Commitments to Fund Commercial Real Estate, Construction, and Land Development Loans [Member] Commitments under home equity lines of credit Commitments under Home Equity Lines of Credit [Member] Commitments under Home Equity Lines of Credit [Member] Unused credit card lines Unused Credit Card Lines [Member] Unused Credit Card Lines [Member] Other loan commitments Other Loan Commitments [Member] Other Loan Commitments [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Total unfunded lending commitments and letters of credit Loss Contingency, Estimate of Possible Loss Carrying amount included in other assets Affordable Housing Program Obligation Amount of future funding commitments included in carrying amount Affordable Housing Program Obligation, Future Funding Included in Carrying Amount Affordable Housing Program Obligation, Future Funding Included in Carrying Amount Short-term construction loans and letter of credit commitments Affordable Housing Program Obligation, Short-term Construction Loans and Letter of Credit Commitments Affordable Housing Program Obligation, Short-term Construction Loans and Letter of Credit Commitments Funded portion of short-term loans and letters of credit Affordable Housing Program Obligation, Funded Portion of Short-term Loans and Letters of Credit Affordable Housing Program Obligation, Funded Portion of Short-term Loans and Letters of Credit Contractual amount net of risk participations Contractual Amount Net of Risk Participations Contractual Amount Net of Risk Participations Maximum potential exposure for sponsored transactions Guarantor Obligations, Liquidation Proceeds, Monetary Amount Guarantor obligations, advanced payment to merchant Guarantor Obligations, Advanced Payment to Merchant Guarantor Obligations, Advanced Payment to Merchant Share-based Payment Arrangement, Noncash Expense [Abstract] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Restricted Share Units Restricted Stock Units (RSUs) [Member] Market Restricted Share Units Market Restricted Stock Units (MRSUs) [Member] Market Restricted Stock Units (MRSUs) [Member] Performance Share Units Performance Share Units (PSUs) [Member] Performance Share Units (PSUs) [Member] Quantity Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Non-vested at January 1, 2019 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Assumed (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Assumed in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Assumed in Period Quantity change by TSR factor (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Quantity Change by TSR Factor Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Quantity Change by TSR Factor Dividend equivalents granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Dividend Equivalents Grants in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Dividend Equivalents Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested at March 31, 2019 (in shares) Weighted-Average Grant Date Fair Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Non-vested at January 1, 2019 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Assumed (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Assumed in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Assumed in Period, Weighted Average Grant Date Fair Value Quantity change by TSR factor (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Quality Change by TSR Factor, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Quality Change by TSR Factor, Weighted Average Grant Date Fair Value Dividend equivalents granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Dividend Equivalents Granted, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Dividend Equivalents Granted, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Non-vested at March 31, 2019 (in dollars per share) Assets and Liabilities, Lessee [Abstract] Assets and Liabilities, Lessee [Abstract] Assets operating Total leased assets Leases, Right-of-Use Asset Leases, Right-of-Use Asset Liabilities operating Present value of lease liabilities Finance Lease, Liability Total lease liabilities Leases, Liability Leases, Liability Finance lease asset, accumulated amortization Finance Lease, Right-of-Use Asset, Accumulated Amortization Finance Lease, Right-of-Use Asset, Accumulated Amortization Lease, Cost [Abstract] Lease, Cost [Abstract] Operating lease cost, net Operating Lease, Cost Amortization of leased assets Finance Lease, Right-of-Use Asset, Amortization Interest on lease liabilities Finance Lease, Interest Expense Sublease income Sublease Income Net lease cost Lease, Cost Rental income Rental Income, Nonoperating Weighted-average remaining lease term (years), Operating leases Operating Lease, Weighted Average Remaining Lease Term Weighted-average discount rate (percentage), Operating leases Operating Lease, Weighted Average Discount Rate, Percent Weighted-average remaining lease term (years), Finance leases Finance Lease, Weighted Average Remaining Lease Term Weighted-average discount rate (percentage), Finance leases Finance Lease, Weighted Average Discount Rate, Percent Operating cash flows from operating leases Operating Lease, Payments Operating cash flows from finance leases Finance Lease, Interest Payment on Liability Financing cash flows from finance leases Finance Lease, Principal Payments Maturity of Lease Liabilities, Operating Leases Lessee, Operating Lease, Liability, Payment, Due [Abstract] 2019 Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating Lease, Liability, Payments, Due Year Five After 2023 Lessee, Operating Lease, Liability, Payments, Due after Year Five Total lease payments Lessee, Operating Lease, Liability, Payments, Due Less: Imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities Maturity of Lease Liabilities, Finance Leases Finance Lease, Liability, Payment, Due [Abstract] 2019 Finance Lease, Liability, Payments, Remainder of Fiscal Year 2020 Finance Lease, Liability, Payments, Due Year Two 2021 Finance Lease, Liability, Payments, Due Year Three 2022 Finance Lease, Liability, Payments, Due Year Four 2023 Finance Lease, Liability, Payments, Due Year Five After 2023 Finance Lease, Liability, Payments, Due after Year Five Total lease payments Finance Lease, Liability, Payment, Due Less: Imputed interest Finance Lease, Liability, Undiscounted Excess Amount Maturity of Lease Liabilities, Total Finance and Operating Lease Liabilities, Payments, Due [Abstract] Finance and Operating Lease Liabilities, Payments, Due [Abstract] 2019 Lessee, Operating and Finance Lease, Liability, Payments, Remainder of Fiscal Year Lessee, Operating and Finance Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating and Finance Lease, Liability, Payments, Due Year Two Lessee, Operating and Finance Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating and Finance Lease, Liability, Payments, Due Year Three Lessee, Operating and Finance Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating and Finance Lease, Liability, Payments, Due Year Four Lessee, Operating and Finance Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating and Finance Lease, Liability, Payments, Due Year Five Lessee, Operating and Finance Lease, Liability, Payments, Due Year Five After 2023 Lessee, Operating and Finance Lease, Liability, Payments, Due after Year Five Lessee, Operating and Finance Lease, Liability, Payments, Due after Year Five Total lease payments Lessee, Operating and Finance Lease, Liability, Payments, Due Lessee, Operating and Finance Lease, Liability, Payments, Due Less: Imputed interest Lessee, Operating and Finance Lease, Liability, Undiscounted Excess Amount Lessee, Operating and Finance Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities Operating and Finance Lease, Liability Operating and Finance Lease, Liability Minimum lease payments related to operating leases that had not yet commenced Lessee, Operating Lease, Lease Not yet Commenced Lessee, Operating Lease, Lease Not yet Commenced Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Term of contract Lessee, Operating Lease, Term of Contract Number of renewal options Lessee, Operating Lease, Number Of Renewal Options Lessee, Operating Lease, Number Of Renewal Options Statement of Stockholders' Equity [Abstract] Cash dividends declared on common stock (USD per share) Common Stock, Dividends, Per Share, Declared Statement [Table] Statement [Table] Preferred Stock Preferred Stock [Member] Series D Preferred Stock Series D Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Cash dividends declared on preferred stock (USD per share) Preferred Stock, Dividends Per Share, Declared Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] U.S. Government agency securities US Government Agencies Short-term Debt Securities [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] 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 Fair Value Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Derivatives not designated as hedging instruments Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Capital markets income Capital Markets Income [Member] Capital Markets Income [Member] Mortgage derivatives Mortgage Derivative [Member] Mortgage Derivative [Member] Interest rate lock commitments Interest Rate Lock Commitments [Member] Frward commitments to sell fixed-rate mortgage loans Forward commitments to sell fixed-rate mortgage loans [Member] Forward commitments to sell fixed-rate mortgage loans [Member] Capital markets income Other Non Interest Income [Member] Other Non Interest Income [Member] Mortgage banking income Mortgage Banking Income [Member] Mortgage Banking Income [Member] Derivative [Line Items] Derivative [Line Items] Gain (Loss) Recognized in Consolidated Statements of Income Derivative, Gain (Loss) on Derivative, Net Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Salaries and other personnel expense Labor and Related Expense [Member] Labor and Related Expense [Member] Other operating expenses Other Operating Income (Expense) [Member] Non-interest expense Noninterest Expense [Member] Noninterest Expense [Member] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Leases Lessee, Finance Leases [Text Block] Leases Lessee, Operating Leases [Text Block] Actual, Net interest income Interest Income (Expense), Net Pro Forma, Net interest income Business Acquisition, Pro Forma Interest Income, Net Business Acquisition, Pro Forma Interest Income, Net Actual, Non-interest income Noninterest Income Pro Forma, Non-interest income Business Acquisition, Pro Forma Non-interest Income Business Acquisition, Pro Forma Non-interest Income Actual, Net income available to common shareholders Pro Forma, Net income available to common shareholders Business Acquisition, Pro Forma Net Income (Loss) Income Statement [Abstract] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Service charges on deposit accounts Deposit Account [Member] Fiduciary and asset management fees Fiduciary and Trust [Member] Card fees Credit and Debit Card [Member] Brokerage revenue Investment Advisory, Management and Administrative Service [Member] Mortgage banking income Mortgage Banking [Member] Interest income: Revenues [Abstract] Loans, including fees Interest and Fee Income, Loans and Leases Held-in-portfolio Investment securities available for sale Interest Income, Debt Securities, Available-for-sale, Operating Mortgage loans held for sale Interest and Fee Income, Loans Held-for-sale, Mortgages Federal Reserve Bank balances Interest Income, Federal Funds Sold and Securities Purchased under Agreements to Resell Other earning assets Other Interest and Dividend Income Total interest income Interest and Dividend Income, Operating Interest expense: Interest Expense [Abstract] Deposits Interest Expense, Deposits Federal funds purchased, securities sold under repurchase agreements, and other short-term borrowings Interest Expense, Short-term Borrowings Long-term debt Interest Expense, Long-term Debt Total interest expense Interest Expense Net interest income Net interest income after provision for loan losses Interest Income (Expense), after Provision for Loan Loss Non-interest income: Noninterest Income [Abstract] Revenue from contract with customers Revenue from Contract with Customer, Including Assessed Tax Capital markets income Swap Fee Income Swap Fee Income Income from bank-owned life insurance Bank Owned Life Insurance Income Investment securities losses, net Debt and Equity Securities, Gain (Loss) Other non-interest income Noninterest Income, Other Total non-interest income Non-interest expense: Noninterest Expense [Abstract] Salaries and other personnel expense Labor and Related Expense Net occupancy and equipment expense Occupancy, Net Third-party processing expense Information Technology and Data Processing Professional fees Professional Fees FDIC insurance and other regulatory fees F D I C Insurance And Other Regulatory Fees The premium paid to the Federal Deposit Insurance Corporation for deposit insurance plus other regulatory fees including examination fees and Federal Reserve service fees, all of which are included in noninterest expense. Advertising expense Advertising Expense Other operating expenses Other Noninterest Expense Total non-interest expense Noninterest Expense Income before income taxes Income tax expense Less: Preferred stock dividends Dividends, Preferred Stock Net income available to common shareholders Net income per common share, diluted (in dollars per share) Weighted average common shares outstanding, basic (in shares) Weighted average common shares outstanding, diluted (in shares) Other intangible assets, gross carrying amount Finite-Lived Intangible Assets, Gross Other intangible assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Other intangible assets, net carrying amount Finite-Lived Intangible Assets, Net Schedule of Basic And Diluted Earnings per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Total AOCI Attributable to Parent [Member] Net unrealized losses on cash flow hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Net unrealized gains (losses) on investment securities available for sale AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Post-retirement unfunded health benefit Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Valuation Allowance of Deferred Tax Assets SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Balance Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from AOCI Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from adoption of ASU 2018-02 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Securities, After Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Securities, After Tax Cumulative-effect adjustment from adoption of ASU 2016-01 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Investment Transferred from Available-for-sale to Other Assets, after Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Investment Transferred from Available-for-sale to Other Assets, after Tax Balance Accumulated other comprehensive income (loss) Schedule of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Notional amount Derivative, Notional Amount Fair value of derivative assets Derivative Asset, Fair Value, Amount Not Offset Against Collateral Fair value of derivative liabilities Derivative Liability, Fair Value, Amount Not Offset Against Collateral Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Use of Estimates in the Preparation of Financial Statements Use of Estimates, Policy [Policy Text Block] Purchased Loans Purchased Loans Policy [Policy Text Block] Purchased Loans Policy [Policy Text Block] Non-interest Income - Revenue from Contracts with Customers within the scope of ASC Topic 606 Revenue from Contract with Customer [Policy Text Block] Accounting Standards Updates New Accounting Pronouncements, Policy [Policy Text Block] Shareholders' Equity and Other Comprehensive Income (Loss) Stockholders' Equity Note Disclosure [Text Block] 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] Beginning balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Additions Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions Transfers from non-accretable difference to accretable yield Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion 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) Ending balance Loans and Allowance for Loan Losses Loans, Net of Unearned Income [Text Block] Schedule of Loans, Net of Unearned Income [Text Block] Financial Instruments Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Changes in Fair Value Included in Consolidated Statements of Income Changes In Fair Value Included In Consolidated Statements Of Income [Text Block] Changes In Fair Value Included In Consolidated Statements Of Income [Text Block] Changes in Level 3 Fair Value Measurements Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Assets and Liabilities Measured at Fair Value on Non-Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Assets Measured at Fair Value on a Nonrecurring Basis Assets Measured at Fair Value on a Nonrecurring Basis [Table Text Block] Assets Measured at Fair Value on a Nonrecurring Basis [Table Text Block] Carrying and Estimated Fair Values of Financial Instruments Carried on Balance Sheet Fair Value, by Balance Sheet Grouping [Table Text Block] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] Financial Asset, Period Past Due [Axis] Financial Asset, Period Past Due [Axis] Financial Asset, Period Past Due [Domain] Financial Asset, Period Past Due [Domain] Current Financing Receivables, Current and Less than 30 Days Past Due, and Still Accruing [Member] Financing Receivables, Current and Less than 30 Days Past Due, and Still Accruing [Member] Accruing 30-89 Days Past Due Financing Receivables, 30 to 89 Days Pat Due [Member] Financing Receivables, 30 to 89 Days Pat Due [Member] Accruing 90 Days or Greater Past Due Financing Receivables, 90 to 149 Days Pat Due [Member] Financing Receivables, 90 to 149 Days Pat Due [Member] Total Accruing Past Due Financing Receivables, 150 or More Days Past Due [Member] Financing Receivables, 150 or More Days Past Due [Member] Credit cards Credit Card Receivable [Member] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Loans and leases receivables Non-accrual Financing Receivable, Nonaccrual ASC 310-30 Loans Discount/Premium Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Total loans Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedges Cash Flow Hedging [Member] Fair Value Hedges Fair Value Hedging [Member] Credit Risk Contract Credit Risk Contract [Member] Derivative instruments Derivative Instruments in Hedges, at Fair Value, Net Collateral requirements Derivative, Collateral, Right to Reclaim Cash Variation margin, amount reducing derivative asset Variation margin, amount reducing derivative asset Variation margin, amount reducing derivative asset Impaired loans Collateral Dependent Impaired Loans [Member] Collateral Dependent Impaired Loans [Member] Other loans held for sale Other Loans Held for Sale [Member] Other Loans Held for Sale [Member] Other real estate Other Real Estate [Member] Other Real Estate [Member] Assets, fair value adjustment Assets, Fair Value Adjustment Quantity Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding at January 1, 2019 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Exercised (in shares) Outstanding at June 30, 2019 (in shares) Weighted-Average Exercise Price Per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Outstanding at January 1, 2019 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Assumed (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Assumed in Period, Weighted Average Exercise Price Share-based Compensation Arrangements by Share-based Payment Award, Options, Assumed in Period, Weighted Average Exercise Price Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Outstanding at June 30, 2019 (in dollars per share) Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) Comprehensive Income (Loss) [Table Text Block] Cover page. Entities [Table] Entities [Table] Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series D Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series E Entity Information [Line Items] Entity Information [Line Items] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Document Period End Date Document Period End Date Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Pass Pass [Member]