Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Trading Symbol Trading Symbol Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period 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 Current Reporting Status Entity Current Reporting Status Entity Shell Company Entity Shell Company Entity File Number Entity File Number Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, Address Line Two Entity Address Address Line2 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 Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock Shares Outstanding Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Cash and due from banks Cash And Due From Banks Interest-bearing deposits at other financial institutions Interest Bearing Deposits In Banks Total cash and cash equivalents Cash And Cash Equivalents At Carrying Value Available for sale securities, at fair value Available For Sale Securities Loans held for investment Loans And Leases Receivable Gross Carrying Amount Less: allowance for loan losses Loans And Leases Receivable Allowance Loans, net Loans And Leases Receivable Net Reported Amount Accrued interest receivable Interest Receivable Premises and equipment, net Property Plant And Equipment Net Other real estate owned Real Estate Acquired Through Foreclosure Federal Home Loan Bank stock Federal Home Loan Bank Stock Bank owned life insurance Bank Owned Life Insurance Goodwill Goodwill Core deposit intangibles, net Finite Lived Intangible Assets Net Other assets Other Assets TOTAL ASSETS Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities And Stockholders Equity [Abstract] LIABILITIES: Liabilities [Abstract] Deposits: Deposits [Abstract] Noninterest-bearing Noninterest Bearing Deposit Liabilities Interest-bearing Interest Bearing Deposit Liabilities [Abstract] Demand Demand Deposit Accounts Money market and savings Deposits Savings Deposits Certificates and other time Time Deposits Total interest-bearing deposits Interest Bearing Deposit Liabilities Total deposits Deposits Accrued interest payable Interest Payable Current And Noncurrent Borrowed funds Debt Longterm And Shortterm Combined Amount Subordinated debt Subordinated Debt Other liabilities Other Liabilities Total liabilities Liabilities COMMITMENTS AND CONTINGENCIES (See Note 13) Commitments And Contingencies SHAREHOLDERS’ EQUITY: Stockholders Equity [Abstract] Preferred stock, $1 par value; 1,000,000 shares authorized; no shares issued or outstanding Preferred Stock Value Common stock, $1 par value; 80,000,000 shares authorized; 21,147,179 shares issued and outstanding at June 30, 2019 and 21,937,740 shares issued and outstanding at December 31, 2018 Common Stock Value Capital surplus Additional Paid In Capital Retained earnings Retained Earnings Accumulated Deficit Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income Loss Net Of Tax Total shareholders’ equity Stockholders Equity TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities And Stockholders Equity Preferred stock, par value (in dollars per share) Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock Shares Authorized Shares issued (in shares) Preferred Stock Shares Issued 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 Issued Common stock, shares outstanding (in shares) Common Stock Shares Outstanding Rebate from correspondent bank Amount of expense for regulatory assessments and Federal Deposit Insurance Corporation (FDIC) insurance. Interest income. Securities. Income Statement [Abstract] Statement [Table] Statement [Table] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] Deposit Account, Nonsufficient Funds Fee [Member] Deposit Account, Nonsufficient Funds Fee Deposit Account Nonsufficient Funds Fee [Member] Deposit Account, Service Charge Fee [Member] Deposit Account, Service Charge Fee Deposit Account Service Charge Fee [Member] Statement [Line Items] Statement [Line Items] INTEREST INCOME: Interest Income [Abstract] Loans, including fees Interest And Fee Income Loans And Leases Securities: Securities [Abstract] Taxable Interest Income Securities Taxable Tax-exempt Interest Income Securities Tax Exempt Deposits in other financial institutions Interest Income Deposits With Financial Institutions Total interest income Interest And Dividend Income Operating INTEREST EXPENSE: Interest Expense [Abstract] Demand, money market and savings deposits Interest Expense N O W Accounts Money Market Accounts And Savings Deposits Certificates and other time deposits Interest Expense Time Deposits Borrowed funds Interest Expense Borrowings Subordinated debt Interest Expense Subordinated Notes And Debentures 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] Revenue from contract with customer Revenue From Contract With Customer Including Assessed Tax Gain on sale of securities Debt And Equity Securities Gain Loss Gain on sale of other real estate Gains Losses On Sales Of Other Real Estate Bank owned life insurance income Bank Owned Life Insurance Income Rebate from correspondent bank Rebatefromcorrespondentbank Other Noninterest Income Other Operating Income Total noninterest income Noninterest Income NONINTEREST EXPENSE: Noninterest Expense [Abstract] Salaries and employee benefits Labor And Related Expense Net occupancy and equipment Occupancy Net Depreciation Depreciation Nonproduction Data processing and software amortization Information Technology And Data Processing Professional fees Professional Fees Regulatory assessments and FDIC insurance Regulatory Assessments And F D I C Insurance Core deposit intangibles amortization Amortization Of Intangible Assets Communications Communication Advertising Marketing And Advertising Expense Acquisition and merger-related expenses Business Combination Integration Related Costs Other Other Noninterest Expense Total noninterest expense Noninterest Expense INCOME BEFORE INCOME TAXES Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for income taxes Income Tax Expense Benefit NET INCOME Net Income Loss Available To Common Stockholders Basic EARNINGS PER SHARE: Earnings Per Share [Abstract] Basic Earnings Per Share Basic Diluted Earnings Per Share Diluted Unrealized gain loss on securities. Statement Of Income And Comprehensive Income [Abstract] Net income Net Income Loss Other comprehensive income (loss), before tax: Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent [Abstract] Unrealized gain (loss) on securities: Unrealized Gain Loss On Securities [Abstract] Change in unrealized holding gain (loss) on available for sale securities during the period Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax Reclassification of gain realized through the sale of securities Other Comprehensive Income Loss Reclassification Adjustment From A O C I For Sale Of Securities Before Tax Total other comprehensive income (loss) Other Comprehensive Income Loss Before Tax Portion Attributable To Parent Deferred tax (expense) benefit related to other comprehensive income Other Comprehensive Income Loss Tax Portion Attributable To Parent1 Other comprehensive income (loss), net of tax Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent Comprehensive income Comprehensive Income Net Of Tax Represents the amounts within accumulated other comprehensive income reclassified to retained earnings during the period as a result of tax reform. Stockholders equity adjusted balance. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Capital Surplus Additional Paid In Capital [Member] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income [Member] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] Accounting Standards Update 2017-08 Accounting Standards Update201708 [Member] Balance Balance (in shares) Shares Issued Cumulative effect of change in accounting principle related to ASU 2017-08 Cumulative Effect Of New Accounting Principle In Period Of Adoption Total shareholders' equity at beginning of period, as adjusted Stockholders Equity Adjusted Balance Other comprehensive income (loss) Other Comprehensive Income Loss Net Of Tax Reclassification of amounts within AOCI to retained earnings due to tax reform Reclassifications Of Amounts Within A O C I To Retained Earnings Due To Tax Reform Common stock issued in connection with the exercise of stock options and restricted stock awards Stock Issued During Period Value Share Based Compensation Common stock issued in connection with the exercise of stock options and restricted stock awards (in shares) Stock Issued During Period Shares Share Based Compensation Repurchase of common stock Stock Repurchased During Period Value Repurchase of common stock (in shares) Stock Repurchased During Period Shares Stock based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Balance Balance (in shares) Accretion amortization of discounts and premiums loans. Represents the net amortization of premium on subordinated debt. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method. Represents the net amortization of premium on certificates of deposit. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method. The amount of dividends paid to the company by the Federal Home Loan Bank. Increase decrease in lease right-of-use assets. Increase (decrease) in accrued interest receivable and other assets. Operating lease cash flows. Lease right-of-use asset. Loans transferred to other real estate. Statement Of Cash Flows [Abstract] Business Acquisition Pro Forma Information Nonrecurring Adjustments [Table] Business Acquisition Pro Forma Information Nonrecurring Adjustments [Table] Business Acquisition Business Acquisition [Axis] Business Acquisition, Acquiree Business Acquisition Acquiree [Domain] Lowery bank. Lowery Bank Lowery Bank [Member] Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items] Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items] 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] Depreciation and core deposit intangibles amortization Depreciation And Amortization Provision for loan losses Provision For Loan Lease And Other Losses Net amortization of premium on investments Accretion Amortization Of Discounts And Premiums Investments Excess tax benefit related to the exercise of stock options Excess Tax Benefit From Share Based Compensation Operating Activities Bank owned life insurance Net accretion of discount on loans Accretion Amortization Of Discounts And Premiums Loans Net accretion of discount on subordinated debt Accretion Amortization Of Discounts And Premiums Subordinated Debt Net accretion of discount on certificates of deposit Accretion Amortization Of Discounts And Premiums Certificates Of Deposit Net gain on the sale or write down of premises, equipment and other real estate Gain Loss On Sales Of Assets And Asset Impairment Charges Federal Home Loan Bank stock dividends Federal Home Loan Bank Stock Dividends Stock based compensation expense Share Based Compensation Net change in lease right-of-use assets Increase Decrease In Lease Right Of Use Assets Decrease (increase) n accrued interest receivable and other assets Increase Decrease In Accrued Interest Receivable And Other Assets Increase in accrued interest payable and other liabilities Increase Decrease In Accrued Liabilities And Other Operating Liabilities Net cash provided by operating activities Net Cash Provided By Used In Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities [Abstract] Proceeds from maturities and principal paydowns of available for sale securities Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Proceeds from sales of available for sale securities Proceeds From Sale Of Available For Sale Securities Purchase of available for sale securities Payments To Acquire Available For Sale Securities Debt Net change in total loans Payments For Proceeds From Loans And Leases Purchase of bank premises and equipment Payments To Acquire Property Plant And Equipment Net redemptions (purchases) of Federal Home Loan Bank stock Payments For Proceeds From Federal Home Loan Bank Stock Net cash paid for the LoweryBank branch acquisition Payments To Acquire Businesses Net Of Cash Acquired Net cash (used in) provided by 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 (decrease) increase in noninterest-bearing deposits Net Change Noninterest Bearing Deposits Domestic Net increase in interest-bearing deposits Net Change Interest Bearing Deposits Domestic Paydowns on borrowed funds Repayments Of Debt Proceeds from the issuance of common stock, stock option exercises and the ESPP Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options Repurchase of treasury stock Proceeds From Repurchase Of Equity Net cash provided by financing activities Net Cash Provided By Used In Financing Activities NET CHANGE IN CASH AND CASH EQUIVALENTS Cash And Cash Equivalents Period Increase Decrease CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD CASH AND CASH EQUIVALENTS, END OF PERIOD SUPPLEMENTAL CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Income taxes paid Income Taxes Paid Interest paid Interest Paid Net Operating lease cash flows Operating Lease Cash Flows SUPPLEMENTAL NONCASH DISCLOSURE: Noncash Investing And Financing Items [Abstract] Lease right-of-use asset and liability Lease Right Of Use Asset Loans transferred to other real estate Loans Transferred To Other Real Estate Accounting Policies [Abstract] NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES Basis Of Presentation And Significant Accounting Policies [Text Block] Business Combinations [Abstract] ACQUISITIONS Business Combination Disclosure [Text Block] Goodwill And Intangible Assets Disclosure [Abstract] GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS Goodwill And Intangible Assets Disclosure [Text Block] Investments Debt And Equity Securities [Abstract] SECURITIES Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Loans and Allowance for Loan Losses [Abstract] Loans And Allowance For Loan Losses [Abstract] LOANS AND ALLOWANCE FOR LOAN LOSSES Loans Notes Trade And Other Receivables Disclosure [Text Block] Leases [Abstract] LEASES Lessee Operating Leases [Text Block] Fair Value Disclosures [Abstract] FAIR VALUE Fair Value Disclosures [Text Block] Deposit Liabilities [Abstract] Deposit Liabilities [Abstract] DEPOSITS Deposit Liabilities Disclosures [Text Block] Debt Disclosure [Abstract] BORROWINGS AND BORROWING CAPACITY Debt Disclosure [Text Block] Subordinated Borrowings [Abstract] SUBORDINATED DEBT Subordinated Borrowings Disclosure [Text Block] Income Tax Disclosure [Abstract] INCOME TAXES Income Tax Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] STOCK BASED COMPENSATION Disclosure Of Compensation Related Costs Share Based Payments [Text Block] The entire disclosure for off-balance sheet arrangements, commitments and contingencies. Commitments And Contingencies Disclosure [Abstract] OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES Off Balance Sheet Arrangements Commitments And Contingencies Disclosure [Text Block] Banking And Thrift [Abstract] REGULATORY CAPITAL MATTERS Regulatory Capital Requirements Under Banking Regulations [Text Block] EARNINGS PER COMMON SHARE Earnings Per Share [Text Block] Subsequent Events [Abstract] SUBSEQUENT EVENTS Subsequent Events [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] New Accounting Standards New Accounting Pronouncements Policy Policy [Text Block] Schedule of Purchase Price Allocation Schedule Of Recognized Identified Assets Acquired And Liabilities Assumed Table [Text Block] Tabular disclosure of the fair value of loans acquired. May include such details as the contractual balance, fair value, and discount on the loans. Schedule of Details of Loans Acquired Details Of Loans Acquired Table [Text Block] Schedule of Intangible Assets and Goodwill Schedule Of Intangible Assets And Goodwill Table [Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Scheduleof Finite Lived Intangible Assets Future Amortization Expense Table [Text Block] Available-for-sale Securities Debt Securities Available For Sale Table [Text Block] Investments Classified by Contractual Maturity Date Investments Classified By Contractual Maturity Date Table [Text Block] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Debt Securities Available For Sale Unrealized Loss Position Fair Value Table [Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable Schedule Of Accounts Notes Loans And Financing Receivable [Text Block] Schedule of carrying amount of loans. Carrying Amount of PCI Loans Schedule Of Carrying Amount Of Loans Table [Text Block] Schedule of changes in accretable yield. Changes in Accretable Yield for PCI Loans Schedule Of Changes In Accretable Yield Table [Text Block] Past Due Financing Receivables Past Due Financing Receivables Table [Text Block] Impaired Financing Receivables Impaired Financing Receivables Table [Text Block] Financing Receivable Credit Quality Indicators Financing Receivable Credit Quality Indicators Table [Text Block] Allowance for Credit Losses on Financing Receivables Allowance For Credit Losses On Financing Receivables Table [Text Block] Troubled Debt Restructurings on Financing Receivables Troubled Debt Restructurings On Financing Receivables Table [Text Block] Lessee operating lease supplemental lease information. Supplemental Lease Information Lessee Operating Lease Supplemental Lease Information Table [Text Block] Maturity Analysis of Lease Liabilities Lessee Operating Lease Liability Maturity Table [Text Block] Fair Value, by Balance Sheet Grouping Fair Value By Balance Sheet Grouping [Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Fair Value Measurements, Nonrecurring Fair Value Assets Measured On Nonrecurring Basis [Text Block] Tabular disclosure of time deposits by year of maturity. Schedule of Maturities of Time Deposits Schedule Of Maturities Of Time Deposits Table [Text Block] Schedule of Subordinated Borrowing Schedule Of Subordinated Borrowing [Text Block] Schedule of Share-based Compensation, Stock Options, Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Schedule of Share-based Compensation, Restricted Stock Units Award Activity Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] Schedule of Fair Value, Off-balance Sheet Risks Schedule Of Fair Value Off Balance Sheet Risks [Text Block] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Number of offices in which the entity operates Number of banks in which entity operates. Number of loan production offices in which the entity operates. New Accounting Pronouncement Early Adoption [Table] New Accounting Pronouncement Early Adoption [Table] Geographical Statement Geographical [Axis] Geographical Segment Geographical [Domain] Houston. Houston Houston [Member] Beaumont. Beaumont Beaumont [Member] ASU 2016-02 Accounting Standards Update201602 [Member] ASU 2017-08 New Accounting Pronouncement Early Adoption [Line Items] New Accounting Pronouncement Early Adoption [Line Items] Number of offices in which entity operates Number Of Offices In Which Entity Operates Number of banks in which entity operates Number Of Banks In Which Entity Operates Number of loan production offices in which entity operates Number Of Loan Production Offices In Which Entity Operates Right-of-use assets Operating Lease Right Of Use Asset Lease liabilities Operating Lease Liability Cumulative effect of adopting new accounting principle in period of adoption The number of branch offices operated by the entity. Schedule Of Business Acquisitions By Acquisition [Table] Schedule Of Business Acquisitions By Acquisition [Table] Post Oak Bancshares, Inc. [Member] Post Oak Bancshares, Inc. Post Oak Bancshares Inc [Member] Represents Houston, Texas. Houston, Texas Houston Texas [Member] Beaumont, TX [Member] Beaumont, TX Beaumont T X [Member] Range Range [Axis] Range Range [Member] Minimum Minimum [Member] Maximum Maximum [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Effective date of acquisition Business Acquisition Effective Date Of Acquisition1 Number of branches Number Of Branches Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Per Common Share Or Option To Purchase Common Shares Business acquisition option issued to purchase common shares. Number of shares issued in acquisition Business Acquisition Equity Interests Issued Or Issuable Number Of Shares Issued Cash paid for acquisition Payments To Acquire Businesses Gross Number of shares per common share or option to purchase common shares Business Acquisition Equity Interest Issued Or Issuable Number Of Shares Per Common Share Or Option To Purchase Common Shares Option issued in acquisition to purchase common shares Business Acquisition Option Issued To Purchase Common Shares Options exercised Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Business acquisition, share price Business Acquisition Share Price Business acquisition, equity transaction value Business Acquisition Equity Interest Issued Or Issuable Value Assigned Goodwill, acquired during period Goodwill Acquired During Period Intangibles, useful life Finite Lived Intangible Asset Useful Life Business acquisition option value issued to purchase common shares. Business combination cash in lieu of fractional shares. Amount of investment securities acquired at the acquisition date. Business combination recognized identifiable assets acquired and liabilities assumed loans. The aggregate of all deposit liabilities assumed at the acquisition date. Business combination recognized identifiable assets acquired and liabilities assumed other borrowed funds. Amount of other liabilities assumed at the acquisition date. Common shares issued (8,402,010 shares) Business Combination Consideration Transferred Equity Interests Issued And Issuable Stock options issued (299,352) Business Acquisition Option Value Issued To Purchase Common Shares Cash in lieu of fractional shares Business Combination Cash In Lieu Of Fractional Shares Total consideration paid Business Combination Consideration Transferred1 Cash and cash equivalents Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents Investment securities Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Investment Securities Loans Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loans Premises and equipment Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Property Plant And Equipment Core deposit intangibles Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangible Assets Other Than Goodwill Other assets Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Noncurrent Assets Total assets acquired Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets Deposits Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Deposits Other borrowed funds Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Borrowed Funds Other liabilities Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Liabilities Total liabilities assumed Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liabilities Fair value of net assets acquired Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net Goodwill resulting from acquisition Amount of loans and leases held in portfolio at the acquisition date. Disclosure of the amount of the the discount on acquired loans receivable. Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Domain] Commercial and industrial Commercial Portfolio Segment [Member] Portfolio segment of the company's total financing receivables related to commercial real estate. Real estate Real Estate Porfolio Segment [Member] Consumer and other Consumer Portfolio Segment [Member] Class of Financing Receivable, Type Financing Receivable Recorded Investment By Class Of Financing Receivable [Axis] Class of Financing Receivable, Type Financing Receivable Recorded Investment Class Of Financing Receivable [Domain] Represents commercial real estate including multi-family residential but not construction and land development. Commercial real estate (including multi-family residential) Commercial Real Estate Including Multi Family Residential But Not Construction And Land Development [Member] Information pertaining to commercial real estate construction and land development. Commercial real estate construction and land development Commercial Real Estate Construction And Land Development [Member] Represents real estate for 1-4 family residential including home equity. 1-4 family residential (including home equity) Oneto Four Family Residential Including Home Equity [Member] Represents information pertaining to residential construction. Residential construction Residential Construction [Member] Measurement Basis Fair Value By Measurement Basis [Axis] Fair Value Disclosure Item Amounts [Default] Portion At Fair Value Fair Value Disclosure [Member] Fair Value Measurement Fair Value Disclosure Item Amounts [Domain] Contractual Balance Carrying Reported Amount Fair Value Disclosure [Member] Fair Value Estimate Of Fair Value Fair Value Disclosure [Member] Acquired loans receivable Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loans Receivable Discount Business Combination Loans Receivable Discount Pre-tax acquisition and merger-related expenses Business Combination Acquisition Related Costs Business combination recognized Iidentifiable assets acquired and liabilities assumed customer deposits. Business acquisition, customer deposits balances Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Customer Deposits Business acquisition, loans Schedule Of Finite Lived Intangible Assets [Table] Schedule Of Finite Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class Finite Lived Intangible Assets By Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name Finite Lived Intangible Assets Major Class Name [Domain] Core Deposit Intangible Assets Core Deposits [Member] Finite Lived Intangible Assets [Line Items] Finite Lived Intangible Assets [Line Items] Goodwill Goodwill Roll Forward Balance, beginning Measurement period adjustment Goodwill Purchase Accounting Adjustments Balance, ending Core Deposit Intangible Assets Finite Lived Intangible Assets Roll Forward Balance, beginning Amortization Balance, ending Represents the acquisition of F&M Bancshares, Inc. Acquisition of F&M Acquisition Of F M [Member] Goodwill impairment Goodwill Impaired Accumulated Impairment Loss Remaining 2019 Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year 2020 Finite Lived Intangible Assets Amortization Expense Year Two 2021 Finite Lived Intangible Assets Amortization Expense Year Three 2022 Finite Lived Intangible Assets Amortization Expense Year Four 2023 Finite Lived Intangible Assets Amortization Expense Year Five Thereafter Finite Lived Intangible Assets Amortization Expense After Year Five Total Schedule Of Available For Sale Securities [Table] Schedule Of Available For Sale Securities [Table] Financial Instrument Financial Instrument [Axis] Financial Instruments Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] U.S. Government and agency securities U S Government Agencies Debt Securities [Member] Municipal securities U S States And Political Subdivisions [Member] This category includes agency mortgage-backed pass-through securities. Agency mortgage-backed pass-through securities Agency Mortgage Backed Pass Through Securities [Member] Agency collateralized mortgage obligations Collateralized Mortgage Obligations [Member] Corporate bonds and other Corporate Debt Securities [Member] Debt Securities, Available-for-sale [Line Items] Schedule Of Available For Sale Securities [Line Items] Amortized Cost Available For Sale Debt Securities Amortized Cost Basis Gross Unrealized Gains Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Gross Unrealized Losses Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Fair Value Available For Sale Securities Debt Securities Amortized Cost Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis [Abstract] Due in one year or less Available For Sale Securities Debt Maturities Within One Year Amortized Cost Due after one year through five years Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost Due after five years through ten years Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost Due after ten years Available For Sale Securities Debt Maturities After Ten Years Amortized Cost Subtotal Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis Agency mortgage-backed pass through and collateralized mortgage obligation securities Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost Fair Value Available For Sale Securities Debt Maturities Single Maturity Date [Abstract] Due in one year or less Available For Sale Securities Debt Maturities Within One Year Fair Value Due after one year through five years Available For Sale Securities Debt Maturities After One Through Five Years Fair Value Due after five years through ten years Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value Due after ten years Available For Sale Securities Debt Maturities After Ten Years Fair Value Subtotal Available For Sale Securities Debt Maturities Single Maturity Date Agency mortgage-backed pass through and collateralized mortgage obligation securities Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value Total Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value Debt Securities Available For Sale Unrealized Loss Position Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss Gross realized gains Available For Sale Securities Gross Realized Gains Gross realized losses Available For Sale Securities Gross Realized Losses Net realized gain Available For Sale Securities Gross Realized Gain Loss Net Proceeds from sales of available for sale securities Proceeds From Sale Of Available For Sale Securities Debt Security owned and pledged as collateral Security Owned And Pledged As Collateral Fair Value Schedule Of Accounts Notes Loans And Financing Receivable [Table] Schedule Of Accounts Notes Loans And Financing Receivable [Table] Portfolio segment of the company's total financing receivables related to commercial receivables. Mortgage warehouse Mortgage Warehouse Portfolio Segment [Member] Accounts Notes And Loans Receivable [Line Items] Accounts Notes And Loans Receivable [Line Items] Allowance for loan losses Impaired financing receivable discount. Receivable Type Accounts Notes Loans And Financing Receivable By Receivable Type [Axis] Receivable Receivable Type [Domain] PCI loans. PCI Loans Purchased Credit Impaired Loans [Member] Outstanding balance Impaired Financing Receivable Unpaid Principal Balance Less: Discount Impaired Financing Receivable Discount Recorded investment Impaired Financing Receivable Recorded Investment Class of Financing Receivable, Type of Borrower Class Of Financing Receivable Type Of Borrower [Axis] Class of Financing Receivable, Type of Borrower Class Of Financing Receivable Type Of Borrower [Domain] Troubled debt restructurings added in reported period. Troubled debt added during quarter Troubled Debt Restructurings Added In Reporting Period [Member] Allowance for loan losses Balance at beginning of period Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Measurement period adjustment Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Additions Reclassifications from nonaccretable Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference Accretion Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Accretion Balance at June 30, 2019 Financing Receivables, 30 to 89 Days Past Due Financing Receivables Period Past Due [Axis] Financing Receivables, Period Past Due Financing Receivables Period Past Due [Domain] Represents financing receivables that are 30 to 89 days past due. Financing Receivables, 30 to 89 Days Past Due Financing Receivables30 To89 Days Past Due [Member] Financing Receivables, Equal to Greater than 90 Days Past Due Financing Receivables Equal To Greater Than90 Days Past Due [Member] Loans Past Due and Still Accruing Financing Receivable Recorded Investment Past Due Nonaccrual Loans Financing Receivable Recorded Investment Nonaccrual Status Current Loans Financing Receivable Recorded Investment Current Total loans evaluated for impairment With no related allowance recorded. With an allowance recorded. With no related allowance recorded: With No Related Allowance Recorded [Abstract] Recorded investment with no related allowance recorded Impaired Financing Receivable With No Related Allowance Recorded Investment Unpaid principal balance with no related allowance recorded Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance With an allowance recorded: With An Allowance Recorded [Abstract] Impaired financing receivable, with related allowance, recorded investment Impaired Financing Receivable With Related Allowance Recorded Investment Impaired financing receivable, with related allowance, unpaid principal balance Impaired Financing Receivable With Related Allowance Unpaid Principal Balance Related Allowance Impaired Financing Receivable Related Allowance Total. Total: Total [Abstract] Recorded Investment Unpaid Principal Balance Average Recorded Investment Impaired Financing Receivable Average Recorded Investment Interest Income Recognized Impaired Financing Receivable Interest Income Accrual Method Internal Credit Assessment Internal Credit Assessment [Axis] Internal Credit Assessment Internal Credit Assessment [Domain] Pass Pass [Member] A category of financing receivables not considered to be special mention, substandard, doubtful, and loss receivables. Watch Watch [Member] Special Mention Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Allowance for loan losses Roll Forward Commercial Real Estate Portfolio Segment Commercial Real Estate Portfolio Segment [Member] PCI Allowance for loan losses: Allowanceforloanlosses Roll Forward Balance, beginning of period Charge-offs Allowance For Loan And Lease Losses Write Offs Recoveries Allowance For Loan And Lease Loss Recovery Of Bad Debts Net recoveries (charge-offs) Allowance For Loan And Lease Losses Writeoffs Net Balance, end of period Allowance for loan losses related to. Allowance for loan losses related to: Allowance For Loan Losses Related To [Abstract] Individually evaluated for impairment Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 Collectively evaluated for impairment Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment Total allowance for loan losses Recorded investment in loans. Recorded investment in loans: Recorded Investment In Loans [Abstract] Individually evaluated for impairment Financing Receivable Individually Evaluated For Impairment Collectively evaluated for impairment Financing Receivable Collectively Evaluated For Impairment Recorded investment Financing Receivable Modifications Recorded Investment Change in method of calculating impairment Allowance For Credit Losses Change In Method Of Calculating Impairment Number of Contracts Financing Receivable Modifications Number Of Contracts2 Pre- Modification of Outstanding Recorded Investment Financing Receivable Modifications Pre Modification Recorded Investment2 Post- Modification of Outstanding Recorded Investment Financing Receivable Modifications Post Modification Recorded Investment2 Troubled debt restructuring, write-down Financing Receivables Impaired Troubled Debt Restructuring Write Down Troubled debt restructuring, addition Financing Receivable Modifications Subsequent Default Recorded Investment1 Modification of outstanding recorded investment Number of defaults on loan that were modified as troubled debt restructurings during the preceding 12 months Financing Receivable Modifications Subsequent Default Number Of Contracts1 Number of leased branch locations and office space along with equipment. Lessee Lease Description [Table] Lessee Lease Description [Table] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Occupancy and equipment expenses. Occupancy and Equipment Expenses Occupancy And Equipment Expenses [Member] Lessee Lease Description [Line Items] Lessee Lease Description [Line Items] Number of leased branch locations and office space along with equipment Number Of Leased Branch Locations And Office Space Along With Equipment Operating lease cost classified as occupancy and equipment expense Operating Lease Cost Short-term lease costs Short Term Lease Cost Operating lease, existence of option to extend Lessee Operating Lease Existence Of Option To Extend Operating lease renewal term Lessee Operating Lease Renewal Term Balance Sheet: Assets And Liabilities Lessee [Abstract] Operating lease asset classified as premises and equipment Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List Operating lease liability classified as other liabilities Operating Lease, Liability, Statement of Financial Position [Extensible List] Operating Lease Liability Statement Of Financial Position Extensible List Income Statement: Income And Expenses Lessee [Abstract] Weighted average lease term, in years Operating Lease Weighted Average Remaining Lease Term1 Weighted average discount rate Operating Lease Weighted Average Discount Rate Percent Lease payments due: Operating Lease Liabilities Payments Due [Abstract] Within one year Lessee Operating Lease Liability Payments Due Next Twelve Months After one but within two years Lessee Operating Lease Liability Payments Due Year Two After two but within three years Lessee Operating Lease Liability Payments Due Year Three After three but within four years Lessee Operating Lease Liability Payments Due Year Four After four but within five years Lessee Operating Lease Liability Payments Due Year Five After five years Lessee Operating Lease Liability Payments Due After Year Five Total lease payments Lessee Operating Lease Liability Payments Due Discount on cash flows Lessee Operating Lease Liability Undiscounted Excess Amount Total lease liability Represents the fair value of loans held for investment (specifically excludes loans held for sale), net of the related allowance. The fair value of accrued interest receivable. The fair value of accrued interest payable. Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Carrying Amount Estimated Fair Value Level 2 Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Level 1 Fair Value Inputs Level1 [Member] Level 2 Fair Value Inputs Level2 [Member] Level 3 Fair Value Inputs Level3 [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] Cash and cash equivalents Cash And Cash Equivalents Fair Value Disclosure Available for sale securities Loans held for investment, net of allowance Loans Held For Investment Net Of Allowance Fair Value Accrued interest receivable Accrued Interest Receivable Fair Value Deposits Deposits Fair Value Disclosure Accrued interest payable Accrued Interest Payable Fair Value Borrowed funds Debt Instrument Fair Value Subordinated debt Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations Measurement Frequency Fair Value By Measurement Frequency [Axis] Fair Value, Measurement Frequency Fair Value Measurement Frequency [Domain] Recurring Basis Fair Value Measurements Recurring [Member] Available for sale securities Collateral Collateral [Axis] Collateral Collateral [Domain] Foreclosed Commercial Real Estate Property Commercial Real Estate [Member] Foreclosed Residential Rental Property Residential Real Estate [Member] Liabilities, fair value disclosure, recurring Liabilities Fair Value Disclosure This element represents the amount of impaired loans receivable reported on the balance sheet at period end measured at fair value. The fair value portion of land and buildings obtained as of the balance sheet date of land and buildings. Nonrecurring Basis Fair Value Measurements Nonrecurring [Member] Commercial real estate (including multi-family residential) Impaired loans: Impaired Loans Receivable Fair Value Other real estate owned Other Real Estate Owned Fair Value Assets and liabilities are measured at fair value, nonrecurring basis Assets Fair Value Disclosure Related allowance Number of properties Number Of Real Estate Properties The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more. Time deposits, at or above FDIC insurance limit Time Deposits At Or Above F D I C Insurance Limit Time deposits 250,000 or more Time Deposits250000 Or More Within one year Time Deposit Maturities Year One After one but within two years Time Deposit Maturities Year Two After two but within three years Time Deposit Maturities Year Three After three but within four years Time Deposit Maturities Year Four After four but within five years Time Deposit Maturities Year Five Total Brokered deposits Interest Bearing Domestic Deposit Brokered Debt Instrument [Table] Debt Instrument [Table] Federal Home Loan Bank Branch Federal Home Loan Bank Advances Branch Of F H L B Bank [Axis] Federal Home Loan Bank Branch Federal Home Loan Bank Advances Branch Of F H L B Bank State [Domain] Federal Home Loan Bank of Dallas Federal Home Loan Bank Of Dallas [Member] Short-term Debt Short Term Debt [Member] Weighted Average Weighted Average [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Expire In remaining month of 2019. Expire in Remaining Month of 2019 Expire In Remaining Month Of2019 [Member] Expire In 2021 Expire in 2021 Expire In2021 [Member] Expire in 2020. Expire in 2020 Expire In2020 [Member] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Amended revolving credit agreement. Amended Revolving Credit Agreement Amended Revolving Credit Agreement [Member] Represents the borrowing agreement with another financial institution. Borrowing Agreement Borrowing Agreement [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Revolving Credit Agreement Revolving Credit Facility [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Prime Rate Prime Rate [Member] Credit Facility With Another Financial Institution [Member] Credit Facility With Another Financial Institution Credit Facility With Another Financial Institution [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum borrowing capacity Line Of Credit Facility Maximum Borrowing Capacity Remaining borrowing capacity Line Of Credit Facility Remaining Borrowing Capacity Outstanding amount Line Of Credit Federal Home Loan Bank, advances Federal Home Loan Bank Advances Branch Of F H L B Bank Amount Of Advances By Branch Federal Home Loan Bank, advances, interest rate Federal Home Loan Bank Advances Branch Of F H L B Bank Interest Rate Letters of credit, outstanding amount Letters Of Credit Outstanding Amount Percentage of debt secured by capital stock. Debt instrument maturity, month and year. Line of Credit Facility, Annual Reduction In Borrowing Capacity Annual reduction in borrowing capacity Lineof Credit Facility Annual Reduction In Borrowing Capacity Basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Interest rate, effective percentage Debt Instrument Interest Rate Effective Percentage Debt instrument maturity, month and year Debt Instrument Maturity Month And Year Percentage of debt secured by capital stock Percentage Of Debt Secured By Capital Stock Represents the period of time over which the Company has the right to defer payment of interest on debentures. Subordinated Borrowing [Table] Subordinated Borrowing [Table] Represents F&M Bancshares, Inc. F&M Bancshares. Inc. Fm Bancshares Inc [Member] Junior Subordinated Debt Junior Subordinated Debt [Member] Fixed-to-Floating Rate Subordinated Notes [Member] Subordinated Notes Issued 2017 Fixedto Floating Rate Subordinated Notes [Member] 3 month LIBOR London Interbank Offered Rate L I B O R [Member] Subordinated Borrowing [Line Items] Subordinated Borrowing [Line Items] Debentures, period over which company may defer interest payments Debentures Period Over Which The Company May Defer Interest Payments Debt instrument, face amount Debt Instrument Face Amount Debt instrument, unamortized discount Debt Instrument Unamortized Discount Junior subordinated debt owed to trusts Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] Represents information pertaining to Farmers & Merchants Capital Trust II. Farmers & Merchants Capital Trust II Farmers Merchants Capital Trust Ii [Member] Represents information pertaining to Farmers & Merchants Capital Trust III. Farmers & Merchants Capital Trust III Farmers Merchants Capital Trust Iii [Member] Issuance Date Debt Instrument Issuance Date1 Trust Preferred Securities Outstanding Junior Subordinated Debt Owed to Trusts Maturity Date Debt Instrument Maturity Date Interest rate, period end Debt Instrument, Issuance Price, Percentage Issuance price, percentage Debt Instrument Issuance Price Percentage Proceeds from issuance of debt Proceeds From Issuance Of Debt Stated percentage Debt Instrument Interest Rate Stated Percentage Redemption price, percentage Debt Instrument Redemption Price Percentage Income tax expense Effective income tax rate reconciliation, percent Effective Income Tax Rate Continuing Operations Unrecognized tax benefits, income tax penalties and interest expense Unrecognized Tax Benefits Income Tax Penalties And Interest Expense Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Employee Stock Option Employee Stock Option [Member] Restricted Stock Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Number of shares authorized (in shares) Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized Share-based compensation expense Allocated Share Based Compensation Expense Represents the total amount of share-base options granted since the inception of the arrangement. Option, cumulative options granted since inception (in shares) Sharebased Compensation Arrangement By Sharebased Payment Award Option Cumulative Options Granted Since Inception Expiration period Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period Award vesting period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Number of Options Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward Options outstanding, beginning balance (in shares) Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Options granted (in shares) Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Options exercised (in shares) Stock Issued During Period Shares Stock Options Exercised Options forfeited (in shares) Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Options outstanding, ending balance (in shares) Number of options vested and exercisable (in shares) Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Weighted Average Exercise Price Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Options outstanding, beginning balance (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Options granted (in dollars per share) Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Options exercised (in dollars per share) Options forfeited (in dollars per share) Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price Options outstanding, ending balance (in dollars per share) Weighted Average Exercise Price, Options vested and exercisable (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Weighted Average Remaining Contractual Term, Options outstanding Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Weighted Average Remaining Contractual Term, Options vested and exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 Aggregate Intrinsic Value, Options outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Aggregate Intrinsic Value, Options vested and exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Unrecognized compensation cost Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options Weighted average period over which unrecognized compensation Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Equity instruments other than options, grants in period (in shares) Stock Issued During Period Shares New Issues Number of Shares Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward Nonvested share awards outstanding, beginning balance (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Share awards granted (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Share awards vested (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Unvested share awards forfeited or cancelled (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Nonvested share awards outstanding, ending balance (in shares) Weighted Average Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Roll Forward Nonvested share awards outstanding, beginning balance (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 Share awards 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 Share awards 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 Unvested share awards forfeited or cancelled (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 Nonvested share awards outstanding, ending balance The contractual amount of fixed-rate financial liabilities, which are not recognized in the financial statements (off-balance-sheet) because they fail to meet some other criterion for recognition. The contractual amount of variable-rate financial liabilities, which are not recognized in the financial statements (off-balance-sheet) because they fail to meet some other criterion for recognition. Schedule Of Fair Value Off Balance Sheet Risks [Table] Schedule Of Fair Value Off Balance Sheet Risks [Table] Commitments to extend credit Commitments To Extend Credit [Member] An irrevocable undertaking (typically by a financial institution) to guarantee payment of a specified financial obligation. Standby letters of credit Standby Letters Of Credit1 [Member] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] Fixed Rate Offbalance Sheet Financial Instrument Fixed Rate Contractual Amount Variable Rate Offbalance Sheet Financial Instrument Variable Rate Contractual Amount The period of time for which commitments to make loans are generally made. Such loans tend to be made for this duration or less. Represents the weighted average maturity for off-balance-sheet fixed rate loan commitments. Represents the interest rate for off-balance-sheet fixed rate loan commitments. Commitments to make loans, period Commitments To Make Loans Period Off-balance-sheet fixed rate loan commitments, weighted average maturity Off Balance Sheet Fixed Rate Loan Commitments Weighted Average Maturity Off-balance-sheet fixed rate loan commitments, interest rate Off Balance Sheet Fixed Rate Loan Commitments Interest Rate Amount resulting from the phase-in of a capital conservation buffer. Capital Conservation Buffer, Increase per Year An additional amount held in risk-based capital designed to ensure that banks build up capital buffers outside periods of stress which can be drawn down as losses are incurred. The requirement is based on simple capital conservation rules designed to avoid breaches of minimum capital requirements. Capital conservation buffer, phase in amount Capital Conservation Buffer Phase In Amount Capital conservation buffer, increase per year Capital Conservation Buffer Increaseper Year Capital conservation buffer Capital Conservation Buffer Total capital. Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Table] Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Table] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Represent information pertaining to Allegiance Bank, the Company's subsidiary. Allegiance Bank Allegiance Bank [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items] Total Capital Total Capital [Abstract] Capital Capital Capital to Risk Weighted Assets Capital To Risk Weighted Assets Capital Required for Capital Adequacy Capital Required For Capital Adequacy Capital Required for Capital Adequacy to Risk Weighted Assets Capital Required For Capital Adequacy To Risk Weighted Assets Plus Capital Conservation Buffer Excess Capital Plus Capital Conservation Buffer to Risk Weighted Assets Excess Capital To Risk Weighted Assets Capital Required to be Well Capitalized Capital Required To Be Well Capitalized Capital Required to be Well Capitalized to Risk Weighted Assets Capital Required To Be Well Capitalized To Risk Weighted Assets Common equity tier1 capital. Common Equity Tier 1 Leverage Capital as defined in the regulations. Common Equity Tier 1 capital divided by risk weighted assets as defined by regulations. The minimum amount of Common Equity Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. The minimum amount of Common Equity Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. Excess Common Equity Tier One Risk Based Capital Excess Common Equity Tier One Risk Based Capital to Risk Weighted Assets The amount of Common Equity Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. The common equity Tier 1 capital ratio (Tier 1 common equity capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. Common Equity Tier 1 Capital Common Equity Tier1 Capital [Abstract] Common Equity Tier 1 Risk Based Capital Common Equity Tier One Risk Based Capital Common Equity Tier 1 Risk Based Capital to Risk Weighted Assets Common Equity Tier One Risk Based Capital To Risk Weighted Assets Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy Common Equity Tier One Risk Based Capital Required For Capital Adequacy Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Plus Common Equity Tier 1 Risk Based Capital Excess Common Equity Tier One Risk Based Capital Plus Common Equity Tier 1 Risk Based Capital to Risk Weighted Assets Excess Common Equity Tier One Risk Based Capitalto Risk Weighted Assets Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized Common Equity Tier One Risk Based Capital Required To Be Well Capitalized Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Common Equity Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Tier I Capital. Tier 1 Capital Tier I Capital [Abstract] Tier 1 Risk Based Capital Tier One Risk Based Capital Tier 1 Risk Based Capital to Risk Weighted Assets Tier One Risk Based Capital To Risk Weighted Assets Tier 1 Risk Based Capital Required for Capital Adequacy Tier One Risk Based Capital Required For Capital Adequacy Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Plus Tier 1 Risk Based Capital Excess Tier One Risk Based Capital Plus Tier 1 Risk Based Capital to Risk Weighted Assets Excess Tier One Risk Based Capital To Risk Weighted Assets Tier 1 Risk Based Capital Required to be Well Capitalized Tier One Risk Based Capital Required To Be Well Capitalized Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Tier I capital. Tier 1 Capital Tier I Capital Abstract0 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 Tier One Leverage Capital Required For Capital Adequacy Tier 1 Leverage Capital Required for Capital Adequacy to Average Assets Tier One Leverage Capital Required For Capital Adequacy To Average Assets Plus Tier 1 Leverage Capital Excess Tier One Leverage Capital Plus Tier 1 Leverage Capital to Average Assets Excess Tier One Leverage Capital 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 Net income attributable to shareholders Basic: Earnings Per Share Basic [Abstract] Weighted average shares outstanding (in shares) Weighted Average Number Of Shares Outstanding Basic Diluted: Earnings Per Share Diluted [Abstract] Add incremental shares for: Weighted Average Number Diluted Shares Outstanding Adjustment [Abstract] Dilutive effect of stock option exercises (in shares) Incremental Common Shares Attributable To Share Based Payment Arrangements Total (in shares) Weighted Average Number Of Diluted Shares Outstanding Weighted average shares outstanding (in dollars per share) Total (in dollars per share) Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Type of Arrangement and Non-arrangement Transactions Type Of Arrangement [Axis] Arrangements and Non-arrangement Transactions Arrangements And Nonarrangement Transactions [Member] Purchase agreement. Purchase Agreement Purchase Agreement [Member] Name of Property Real Estate And Accumulated Depreciation Description Of Property [Axis] Name of Property Real Estate And Accumulated Depreciation Name Of Property [Domain] Property one. Property One Property One [Member] Property two. Property Two Property Two [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Stock repurchase program authorizing to repurchase Stock Repurchase Program Number Of Shares Authorized To Be Repurchased Common stock expiration date Stock Repurchase Program Expiration Date Area of land and building Area Of Land Leasable area Net Rentable Area Purchase price of Properties Payments To Acquire Buildings