Cover [Abstract] Document Quarterly Report Document Transition Report Document Period End Date Entity Registrant Name Entity Current Reporting Status Trading Symbol Title of 12(b) Security Security Exchange Name Entity File Number Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Document Type Entity Interactive Data Current Current Fiscal Year End Date Entity Central Index Key Document Fiscal Period Focus Document Fiscal Year Focus Amendment Flag Entity Address, Address Line Two Statement of Financial Position [Abstract] Assets [Abstract] Assets Interest Earning Balances Due From Depository Institutions Interest-earning balances due from depository institutions Interest earning balances due from depository institutions. Interest Earning Balances Due from Federal Reserve Interest-earning balances due from Federal Reserve Interest-earning balances due from Federal Reserve. Cash and Due from Banks Cash and due from banks Federal Home Loan Bank Stock Investment in stock of Federal Home Loan Bank (FHLB) Finite-Lived Intangible Assets, Net Intangibles Goodwill Goodwill Debt Securities, Held-to-maturity Investment securities held-to-maturity (with fair value of $1,085,481 at March 31, 2021, and $604,223 at December 31, 2020) Amortized Cost, Held-to-maturity Investment securities held-to-maturity Income Tax Asset Net Income taxes Income tax asset net Interest Receivable Accrued interest receivable Loans and Leases Receivable, Net of Deferred Income Loans and lease finance receivables Total loans, at amortized cost Marketable Securities Total investment securities Other Assets Other assets Other Real Estate Other real estate owned (OREO) Property, Plant and Equipment, Net Premises and equipment, net Loans and Leases Receivable, Net Amount Net loans and lease finance receivables Net loans and lease finance receivables Total loans, net of allowance for loan losses Cash and Cash Equivalents, at Carrying Value Total cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Total cash and cash equivalents Bank Owned Life Insurance Bank owned life insurance (BOLI) Debt Securities, Available-for-sale Investment securities available-for-sale, at fair value (with amortized cost of $2,797,990 at March 31, 2021, and $2,344,174 at December 31, 2020) Fair Value, Available-for-sale Total Available-for-sale Securities, Debt Maturities, Available-for-sale, Fair Value Investment securities available-for-sale Loans and Leases Receivable, Allowance Allowance for credit losses Less: Allowance for credit losses Beginning Balance Ending Balance Assets Total assets Liabilities and Equity [Abstract] Liabilities and Stockholders' Equity Liabilities Total liabilities Liabilities [Abstract] Liabilities: Deposits [Abstract] Deposits: Interest-bearing Deposit Liabilities Interest-bearing Noninterest-bearing Deposit Liabilities Noninterest-bearing Deposits Total deposits Deferred Compensation Liability, Current and Noncurrent Deferred compensation Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Junior subordinated debentures Other Borrowings Other borrowings Other Liabilities Other liabilities Securities Sold under Agreements to Repurchase Customer repurchase agreements Liabilities and Equity Total liabilities and stockholders' equity Stockholders' Equity Attributable to Parent [Abstract] Stockholders' Equity Common Stocks, Including Additional Paid in Capital Common stock, authorized, 225,000,000 shares without par; issued and outstanding 135,919,625 at March 31, 2021, and 135,600,501 at December 31, 2020 Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income, net of tax Stockholders' Equity Attributable to Parent Total stockholders' equity Beginning balance Ending balance Retained Earnings (Accumulated Deficit) Retained earnings Payable For Securities Purchased Payable for securities purchased Payable for securities purchased. Debt Securities, Held-to-maturity, Fair Value Fair Value, Held-to-maturity Debt Securities, Available-for-sale, Amortized Cost Amortized cost Amortized Cost, Available-for-sale Common Stock, No Par Value Common stock, par value Common Stock, Shares Authorized Common stock, authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Income Statement [Abstract] Statement [Table] Statement [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Credit Card [Member] Bankcard Services [Member] Deposit Account [Member] Service Charges on Deposit Accounts [Member] Fiduciary and Trust [Member] Trust and Investment Services [Member] Trust and Investment Services [Member] Statement [Line Items] Statement [Line Items] Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive income Earnings Per Share, Basic Basic earnings per common share Earnings Per Share, Diluted Diluted earnings per common share Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Earnings before income taxes Income Tax Expense (Benefit) Income taxes Interest and Dividend Income, Operating [Abstract] Interest income: Dividend Income, Operating Dividends from FHLB stock Interest and Dividend Income, Operating Total interest income Interest and Dividend Income, Securities, by Taxable Status [Abstract] Investment securities: Interest Income, Debt Securities, Operating Total investment income Interest and Dividend Income, Securities, Operating, Available-for-sale Investment securities available-for-sale Total interest income from available-for-sale securities Interest Income, Debt Securities, Held-to-maturity Investment securities held-to-maturity Total interest income from held-to-maturity securities Interest Earning Deposits With Other Institutions And Federal Funds Sold Interest-earning deposits with other institutions Interest-earning deposits with other institutions and federal funds sold. Interest and Fee Income, Loans and Leases Held-in-portfolio Loans and leases, including fees Net Income (Loss) Attributable to Parent Net earnings Net earnings Noninterest Expense [Abstract] Noninterest expense: Occupancy, Net Occupancy and equipment Noninterest Expense Total noninterest expense Marketing Expense Marketing and promotion Labor and Related Expense Salaries and employee benefits Amortization of Intangible Assets Amortization of intangible assets Other Noninterest Expense Other Professional Fees Professional services Computer Software Expense Computer software expense Computer software expense. Noninterest Income [Abstract] Noninterest income: Noninterest income: Bank Owned Life Insurance Income BOLI income Noninterest Income, Other Other Other Noninterest Income Total noninterest income Total noninterest income Revenue from Contract with Customer, Including Assessed Tax Revenue from contract with customer, including assessed tax Revenue from contract with customer Gains Losses On Other Real Estate Net Gain on OREO, net Gains losses on other real estate net. Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive (loss) income: Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Less: Income tax benefit (expense) related to items of other comprehensive income Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Other comprehensive (loss) income, net of tax Other comprehensive income (loss) Net change, After-tax Other Comprehensive Income Unrealized Holding Gain Loss On Securities Transferred From Available For Sale To Held To Maturity Before Tax Unrealized (loss) gain on securities arising during the period, before tax Net change in Fair Value for available-for-sale-securities, Cumulative-effect adjustment for unrealized gains on securities transferred from available-for-sale to held-to-maturity, Net of change in the Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity. Interest Expense [Abstract] Interest expense: Interest Expense Total interest expense Interest Expense Borrowings And Customer Repurchase Agreements Borrowings and customer repurchase agreements Interest expense borrowings and customer repurchase agreements. Interest Expense, Deposits Deposits Interest Expense, Subordinated Notes and Debentures Junior subordinated debentures Interest Income (Expense), after Provision for Loan Loss Net interest income after (recapture of) provision for credit losses Interest Income (Expense), Net Net interest income before (recapture of) provision for credit losses Recapture of Provision For Loan and Lease Losses (Recapture of) provision for credit losses Recapture of provision for loan and lease losses. Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Including Additional Paid in Capital [Member] Common Stock [Member] Retained Earnings [Member] Retained Earnings [Member] AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Member] Dividends, Common Stock, Cash Cash dividends declared on common stock Shares, Issued Beginning balance, shares Ending balance, shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Shares issued pursuant to stock-based compensation plan, shares Stock Issued During Period, Value, Stock Options Exercised Exercise of stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options, shares Stock Repurchased During Period, Value Repurchase of common stock Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Shares issued pursuant to stock-based compensation plan Stock Repurchased During Period, Shares Repurchase of common stock, shares Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Revision of Prior Period [Axis] Revision of Prior Period [Domain] Revision of Prior Period, Accounting Standards Update, Adjustment [Member] Cumulative adjustment upon adoption of ASU 2016-13 [ Member] Common Stock, Dividends, Per Share, Declared Cash dividends per common share Statement of Cash Flows [Abstract] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Net (decrease) increase in cash and cash equivalents Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net earnings to net cash provided by operating activities: Accretion (Amortization) of Discounts and Premiums, Investments Net amortization of premiums and discounts on investment securities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Total adjustments Gains (Losses) on Sales of Other Real Estate Gain on sale of other real estate owned Gain on OREO, net Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Accretion Accretion of discount for acquired loans, net Depreciation, Amortization and Accretion, Net Depreciation and amortization, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Change in other assets and liabilities Period Changes in Bank Owned Life Insurance Increase in BOLI Period changes in bank owned life insurance. Share-based Compensation Stock-based compensation Net Cash Provided by (Used in) Operating Activities Net cash provided by operating activities Gain (Loss) on Sale of Assets and Asset Impairment Charges Gain on sale of building, net Provision for Other Credit Losses (Recapture of) provision for credit losses Net Cash Provided by (Used in) Investing Activities [Abstract] Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities Net cash (used in) provided by investing activities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Proceeds from maturity of investment securities available-for-sale Payments For Proceeds from Interest Earning Assets Net change in interest-earning balances from depository institutions Payments for proceeds from interest earning assets. Proceeds from Life Insurance Policy Proceeds from BOLI death benefit Payments for (Proceeds from) Loans and Leases Net decrease in loan and lease finance receivables Payments to Acquire Property, Plant, and Equipment Purchase of premises and equipment Payments to Acquire Equity Method Investments Net increase in equity investments Payments to Acquire Held-to-maturity Securities Purchases of investment securities held-to-maturity Proceeds from Sale of Other Real Estate Proceeds from sales of other real estate owned Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Proceeds from repayment and maturity of investment securities held-to-maturity Proceeds From Repayment Of Available For Sale Investment Securities Proceeds from repayment of investment securities available-for-sale Proceeds from repayment of available-for-sale investment securities. Payments to Acquire Debt Securities, Available-for-sale Purchases of investment securities available-for-sale Proceeds from Sale of Buildings Proceeds from sale of building, net of selling costs Net Cash Provided by (Used in) Financing Activities [Abstract] Cash Flows from Financing Activities Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Increase (Decrease) in Other Deposits Net increase in other deposits Increase (Decrease) in Time Deposits Net increase in time deposits Payments for Repurchase of Common Stock Repurchase of common stock Payments of Ordinary Dividends, Common Stock Cash dividends on common stock Proceeds from Stock Options Exercised Proceeds from exercise of stock options Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase Net increase (decrease) in customer repurchase agreements Net Cash Provided by (Used in) Operating Activities [Abstract] Cash Flows from Operating Activities Interest Paid, Including Capitalized Interest, Operating and Investing Activities Interest paid Proceeds from Fees Received Service charges and other fees received Proceeds from Interest and Dividends Received Interest and dividends received Payments to Suppliers and Employees Net cash paid to vendors, employees and others Income Taxes Income taxes Income taxes. Other Noncash Investing and Financing Items [Abstract] Supplemental Disclosure of Non-cash Investing Activities Liabilities Assumed Securities purchased and not settled Reconciliation Of Net Earnings To Net Cash Provided By Operating Activities [Abstract] Reconciliation of Net Earnings to Net Cash Provided by Operating Activities Reconciliation Of Net Earnings To Net Cash Provided By Operating Activities [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Reserve for Unfunded Loan Commitments Nature of Operations [Text Block] Business