Allegiance Bancshares, Inc.

$ Overview Financials Valuation SEC Filings Company Website

2021 Form 10-K Financial Statement

#000164208122000007 Filed on February 25, 2022

Income Statement

Concept	2021	2020 Q4	2020

Balance Sheet

Concept	2021	2020 Q4	2020
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents		$422.8M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$63.70M	$70.69M	$70.70M
YoY Change	-9.9%	5.83%	5.84%
Goodwill		$223.6M
YoY Change		0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$7.105B	$6.050B	$6.050B
YoY Change	17.44%	21.18%	21.18%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$1.800M	$2.700M	$2.700M
YoY Change	-33.33%	-37.21%	-37.21%
Accrued Expenses	$10.40M	$11.90M	$11.90M
YoY Change	-12.61%	3.48%	3.48%
Deferred Revenue
YoY Change
Short-Term Debt
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$12.20M	$14.60M	$14.60M
YoY Change	-16.44%	-7.59%	-7.59%
LONG-TERM LIABILITIES
Long-Term Debt	$198.8M	$263.8M	$263.8M
YoY Change	-24.64%	43.92%	43.92%
Other Long-Term Liabilities	$29.90M	$24.60M	$24.60M
YoY Change	21.54%	57.69%	57.69%
Total Long-Term Liabilities	$228.7M	$288.4M	$288.4M
YoY Change	-20.7%	45.0%	45.0%
TOTAL LIABILITIES
Total Short-Term Liabilities	$12.20M	$14.60M	$14.60M
Total Long-Term Liabilities	$228.7M	$288.4M	$288.4M
Total Liabilities	$6.289B	$5.291B	$5.292B
YoY Change	18.84%	23.55%	23.55%
SHAREHOLDERS EQUITY
Retained Earnings		$195.2M
YoY Change		19.5%
Common Stock		$20.21M
YoY Change		-1.54%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$816.5M	$758.7M	$758.7M
YoY Change
Total Liabilities & Shareholders Equity	$7.105B	$6.050B	$6.050B
YoY Change	17.44%	21.18%	21.18%

Cashflow Statement

Concept	2021	2020 Q4	2020

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0001642081
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Amendment Flag AmendmentFlag	false
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CY2021Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
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CY2020Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	001-37585
CY2021	dei	Entity Registrant Name EntityRegistrantName	Allegiance Bancshares, Inc.
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	TX
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	26-3564100
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	8847 West Sam Houston Parkway, N.
CY2021	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 200
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Houston
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	TX
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	77040
CY2021	dei	City Area Code CityAreaCode	281
CY2021	dei	Local Phone Number LocalPhoneNumber	894-3200
CY2021	dei	Security12b Title Security12bTitle	Common Stock, par value $1.00 per share
CY2021	dei	Trading Symbol TradingSymbol	ABTX
CY2021	dei	Security Exchange Name SecurityExchangeName	NASDAQ
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CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
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CY2021	dei	Auditor Firm AuditorFirmId	173
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CY2020	us-gaap	Noninterest Expense NoninterestExpense	127494000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	120635000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	99894000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	55971000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	66386000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18341000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10437000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	13427000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	81553000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	45534000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	52959000	USD
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.04
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.23
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.50
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.22
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.47
CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.48
CY2020	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.40
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0
CY2021	us-gaap	Net Income Loss NetIncomeLoss	81553000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	45534000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	52959000	USD
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-21696000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	38920000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	11308000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	49000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	287000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	1459000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	1477000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	-1252000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	0	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	225000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	USD
CY2021	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-20493000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	37381000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	9849000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-4304000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	7850000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	2061000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-16189000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	29531000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7788000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	65364000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	75065000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	60747000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-87000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	702984000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	52959000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	7788000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3412000	USD
CY2019	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	58663000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3100000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	709865000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	45534000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	29531000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	8165000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	2569000	USD
CY2020	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	18582000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3425000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	758669000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	81553000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-16189000	USD
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	9697000	USD
CY2021	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3812000	USD
CY2021	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	5659000	USD
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3979000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	816468000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	81553000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	45534000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	52959000	USD
CY2021	us-gaap	Depreciation And Amortization DepreciationAndAmortization	7550000	USD
CY2020	us-gaap	Depreciation And Amortization DepreciationAndAmortization	7638000	USD
CY2019	us-gaap	Depreciation And Amortization DepreciationAndAmortization	7903000	USD
CY2021	abtx	Recapture Of Provision For Credit Losses RecaptureOfProvisionForCreditLosses	-2322000	USD
CY2020	abtx	Recapture Of Provision For Credit Losses RecaptureOfProvisionForCreditLosses	27374000	USD
CY2019	abtx	Recapture Of Provision For Credit Losses RecaptureOfProvisionForCreditLosses	5939000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2783000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-7059000	USD
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-7764000	USD
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-3731000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-4051000	USD
CY2021	abtx	Excess Tax Benefit From Stock Based Compensation ExcessTaxBenefitFromStockBasedCompensation	620000	USD
CY2020	abtx	Excess Tax Benefit From Stock Based Compensation ExcessTaxBenefitFromStockBasedCompensation	149000	USD
CY2019	abtx	Excess Tax Benefit From Stock Based Compensation ExcessTaxBenefitFromStockBasedCompensation	11000	USD
CY2021	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	554000	USD
CY2020	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	582000	USD
CY2019	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	624000	USD
CY2021	abtx	Accretion Amortization Of Discounts And Premiums Loans AccretionAmortizationOfDiscountsAndPremiumsLoans	458000	USD
CY2020	abtx	Accretion Amortization Of Discounts And Premiums Loans AccretionAmortizationOfDiscountsAndPremiumsLoans	2508000	USD
CY2019	abtx	Accretion Amortization Of Discounts And Premiums Loans AccretionAmortizationOfDiscountsAndPremiumsLoans	8853000	USD
CY2021	abtx	Accretion Amortization Of Discounts And Premiums Subordinated Debt AccretionAmortizationOfDiscountsAndPremiumsSubordinatedDebt	-114000	USD
CY2020	abtx	Accretion Amortization Of Discounts And Premiums Subordinated Debt AccretionAmortizationOfDiscountsAndPremiumsSubordinatedDebt	-113000	USD
CY2019	abtx	Accretion Amortization Of Discounts And Premiums Subordinated Debt AccretionAmortizationOfDiscountsAndPremiumsSubordinatedDebt	-111000	USD
CY2021	abtx	Accretion Amortization Of Discounts And Premiums Certificates Of Deposit AccretionAmortizationOfDiscountsAndPremiumsCertificatesOfDeposit	142000	USD
CY2020	abtx	Accretion Amortization Of Discounts And Premiums Certificates Of Deposit AccretionAmortizationOfDiscountsAndPremiumsCertificatesOfDeposit	356000	USD
CY2019	abtx	Accretion Amortization Of Discounts And Premiums Certificates Of Deposit AccretionAmortizationOfDiscountsAndPremiumsCertificatesOfDeposit	772000	USD
CY2021	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-265000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-258000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	26000	USD
CY2021	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	1317000	USD
CY2020	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	4065000	USD
CY2019	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	0	USD
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	49000	USD
CY2020	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	287000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1459000	USD
CY2021	abtx	Federal Home Loan Bank Stock Dividends FederalHomeLoanBankStockDividends	68000	USD
CY2020	abtx	Federal Home Loan Bank Stock Dividends FederalHomeLoanBankStockDividends	192000	USD
CY2019	abtx	Federal Home Loan Bank Stock Dividends FederalHomeLoanBankStockDividends	403000	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	3979000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	3425000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	3100000	USD
CY2021	abtx	Increase Decrease In Operating Leases IncreaseDecreaseInOperatingLeases	2859000	USD
CY2020	abtx	Increase Decrease In Operating Leases IncreaseDecreaseInOperatingLeases	2627000	USD
CY2019	abtx	Increase Decrease In Operating Leases IncreaseDecreaseInOperatingLeases	2097000	USD
CY2021	abtx	Increase Decrease In Accrued Interest Receivable And Other Assets IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets	1261000	USD
CY2020	abtx	Increase Decrease In Accrued Interest Receivable And Other Assets IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets	24964000	USD
CY2019	abtx	Increase Decrease In Accrued Interest Receivable And Other Assets IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets	111000	USD
CY2021	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	4671000	USD
CY2020	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	2395000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	3053000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	107381000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	61063000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	66867000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3281513000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3959259000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3462495000	USD
CY2021	abtx	Proceeds From Sales And Calls Of Available For Sale Securities ProceedsFromSalesAndCallsOfAvailableForSaleSecurities	4898000	USD
CY2020	abtx	Proceeds From Sales And Calls Of Available For Sale Securities ProceedsFromSalesAndCallsOfAvailableForSaleSecurities	38106000	USD
CY2019	abtx	Proceeds From Sales And Calls Of Available For Sale Securities ProceedsFromSalesAndCallsOfAvailableForSaleSecurities	173024000	USD
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	4315947000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	4362521000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	3663770000	USD
CY2021	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	-277440000	USD
CY2020	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	591471000	USD
CY2019	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	165984000	USD
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	2932000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	7182000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	13385000	USD
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	1738000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	4027000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	1871000	USD
CY2021	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	1534000	USD
CY2020	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	1322000	USD
CY2019	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-5102000	USD
CY2021	us-gaap	Other Payments To Acquire Businesses OtherPaymentsToAcquireBusinesses	0	USD
CY2020	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	15000000	USD
CY2019	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	0	USD
CY2020	us-gaap	Other Payments To Acquire Businesses OtherPaymentsToAcquireBusinesses	0	USD
CY2019	us-gaap	Other Payments To Acquire Businesses OtherPaymentsToAcquireBusinesses	32867000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-754824000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-961104000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-233514000	USD
CY2021	us-gaap	Net Change Noninterest Bearing Deposits Domestic NetChangeNoninterestBearingDepositsDomestic	538518000	USD
CY2020	us-gaap	Net Change Noninterest Bearing Deposits Domestic NetChangeNoninterestBearingDepositsDomestic	452335000	USD
CY2019	us-gaap	Net Change Noninterest Bearing Deposits Domestic NetChangeNoninterestBearingDepositsDomestic	29052000	USD
CY2021	us-gaap	Net Change Interest Bearing Deposits Domestic NetChangeInterestBearingDepositsDomestic	520781000	USD
CY2020	us-gaap	Net Change Interest Bearing Deposits Domestic NetChangeInterestBearingDepositsDomestic	468402000	USD
CY2019	us-gaap	Net Change Interest Bearing Deposits Domestic NetChangeInterestBearingDepositsDomestic	361536000	USD
CY2021	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-50000000	USD
CY2020	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	65000000	USD
CY2019	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-149990000	USD
CY2021	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	-15569000	USD
CY2021	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
CY2020	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	58601000	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	9697000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	8165000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	0	USD
CY2021	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	3812000	USD
CY2020	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	2569000	USD
CY2019	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	3412000	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	5659000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	18582000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	58663000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	982186000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	976559000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	243948000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	334743000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	76518000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	77301000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	422766000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	346248000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	268947000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	757509000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	422766000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	346248000	USD
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	19250000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	15100000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	15400000	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	25568000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	40704000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	51856000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	3433000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	3282000	USD
CY2021Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	26000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	3543000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1446000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3056000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	13277000	USD
CY2021	abtx	Loans Transferred To Other Real Estate LoansTransferredToOtherRealEstate	821000	USD
CY2020	abtx	Loans Transferred To Other Real Estate LoansTransferredToOtherRealEstate	9209000	USD
CY2019	abtx	Loans Transferred To Other Real Estate LoansTransferredToOtherRealEstate	7707000	USD
CY2021	abtx	Other Real Estate Transferred To Loans OtherRealEstateTransferredToLoans	8125000	USD
CY2020	abtx	Other Real Estate Transferred To Loans OtherRealEstateTransferredToLoans	2379000	USD
CY2019	abtx	Other Real Estate Transferred To Loans OtherRealEstateTransferredToLoans	0	USD
CY2021	abtx	Branch Assets Transferred To Held For Sale BranchAssetsTransferredToHeldForSale	2925000	USD
CY2020	abtx	Branch Assets Transferred To Held For Sale BranchAssetsTransferredToHeldForSale	0	USD
CY2019	abtx	Branch Assets Transferred To Held For Sale BranchAssetsTransferredToHeldForSale	0	USD
CY2021Q4	abtx	Number Of Offices In Which Entity Operates NumberOfOfficesInWhichEntityOperates	27	office
CY2021Q4	abtx	Number Of Banks In Which Entity Operates NumberOfBanksInWhichEntityOperates	26	office
CY2021	us-gaap	Use Of Estimates UseOfEstimates	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Use of Estimates—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions based on available information. These estimates and assumptions affect the reporting of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.</span>
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Policy For Uncollectible Amounts FinancingReceivableAllowanceForCreditLossesPolicyForUncollectibleAmounts	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">llowance for Credit Losses—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The allowance for credit losses is a valuation account that is established through a provision for (or reversal of) credit losses charged to expense, which represents management’s best estimate of lifetime expected losses based on </span><div style="margin-top:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">reasonable and supportable forecasts, historical loss experience, and other qualitative considerations. The allowance for credit losses includes the allowance for credit losses on loans, which is deducted from the loans’ amortized cost basis to present the net amount expected to be collected on loans, and the allowance for credit losses on unfunded commitments reported in other liabilities. </span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Allowance for Credit Losses on Loans</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Effective January 1, 2020, the Company adopted ASU 2016-13</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"> Financial Instruments – Credit Losses (ASC Topic 326): Measurement of Credit Losses on Financial Instruments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, which replaced the incurred loss methodology with an expected loss methodology that is referred to as the CECL methodology. The level of the allowance is based upon management's evaluation of historical default and loss experience, current and projected economic conditions, asset quality trends, known and inherent risks in the portfolio, adverse situations that may affect the borrowers' ability to repay a loan (including the timing of future payments), the estimated value of any underlying collateral, composition of the loan portfolio, industry and peer bank loan quality indications and other pertinent factors, including regulatory recommendations. The allowance for credit losses on loans maintained by management is believed adequate to absorb all expected future losses in the loan portfolio at the balance sheet date. The Company disaggregates the loan portfolio into pools for purposes of determining the allowance for credit losses. These pools are based on the level at which the Company develops, documents and applies a systematic methodology to determine the allowance for credit losses. </span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Loans with similar risk characteristics are collectively evaluated resulting in loss estimates as determined by applying reserve factors, such as historical lifetime loan loss experience, concentration risk of specific loan types, the volume, growth and composition of the Company’s loan portfolio, current economic conditions and reasonable and supportable forecasted economic conditions that may affect the borrower’s ability to pay and the value of collateral, the evaluation of the Company’s loan portfolio through its internal loan review process, general economic conditions and other qualitative risk factors both internal and external to the Company and other relevant factors, designed to estimate current expected credit losses, to amortized cost balances over the remaining contractual life of the collectively evaluated portfolio. Loans with similar risk characteristics are aggregated into homogeneous pools for assessment. Historical lifetime loan loss experience is determined by utilizing an open-pool (“cumulative loss rate”) methodology. Adjustments to the historical lifetime loan loss experience are made for differences in current loan pool risk characteristics such as portfolio concentrations, delinquency, nonaccrual, and watch list levels, as well as changes in current and forecasted economic conditions such as unemployment rates, property and collateral values, and other indices relating to economic activity. Losses are predicted over a period of time determined to be reasonable and supportable, and at the end of the reasonable and supportable period losses are reverted to long term historical averages. The reasonable and supportable period and reversion period are re-evaluated each year by the Company and are dependent on the current economic environment among other factors. A reasonable and supportable period of twelve months was utilized for all loan pools, followed by an immediate reversion to long term averages. Based on a review of these factors for each loan type, the Company applies an estimated percentage to the outstanding balance of each loan type. </span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Loans that no longer share risk characteristics with the collectively evaluated loan pools are evaluated on an individual basis and are excluded from the collectively evaluated pools. In order to assess which loans are to be individually evaluated, the Company follows a loan review program to evaluate the credit risk in the total loan portfolio and assigns risk grades to each loan. Individual credit loss estimates are typically performed for nonaccrual loans, modified loans classified as troubled debt restructurings and all other loans identified by management. All loans deemed as being individually evaluated are reviewed on a quarterly basis in order to determine whether a specific reserve is required. The Company considers certain loans to be collateral dependent if the borrower is experiencing financial difficulty and management expects repayment for the loan to be substantially through the operation or sale of the collateral. For collateral dependent loans, loss estimates are based on the fair value of collateral, less estimated cost to sell (if applicable). Collateral values supporting individually evaluated loans are assessed quarterly and appraisals are typically obtained at least annually. The Company allocates a specific loan loss reserve on an individual loan basis primarily based on the value of the collateral securing the individually evaluated loan. Through this loan review process, the Company assesses the overall quality of the loan portfolio and the adequacy of the allowance for credit losses on loans while considering risk elements attributable to particular loan types in assessing the quality of individual loans. In addition, for each category of loans, the Company considers secondary sources of income and the financial strength and credit history of the borrower and any guarantors.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A change in the allowance for credit losses on loans can be attributable to several factors, most notably specific reserves for individually evaluated loans, historical lifetime loan loss information, and changes in economic factors and growth in the loan portfolio. Specific reserves that are calculated on an individual basis and the qualitative assessment of all other loans reflect current changes in the credit quality of the loan portfolio. Historical lifetime credit losses, on the other hand, are based on an open-pool (“cumulative loss rate”) methodology, which is then applied to estimate lifetime credit losses in the loan portfolio. The allowance for credit losses on loans is further determined by the size of the loan portfolio subject to the allowance methodology and factors that include Company-specific risk indicators and general economic conditions, both of which are constantly changing. The Company evaluates the economic and portfolio-specific factors on a quarterly basis to determine a qualitative component of the general valuation allowance. These factors include current economic metrics, reasonable and supportable forecasted economic metrics, </span></div><div style="margin-top:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">delinquency trends, credit concentrations, nature and volume of the portfolio and other adjustments for items not covered by specific reserves and historical lifetime loss experience. Based on the Company’s actual historical lifetime loan loss experience relative to economic and loan portfolio-specific factors at the time the losses occurred, management is able to identify the probable level of lifetime losses as of the date of measurement. The Company’s analysis of qualitative, or economic, factors on pools of loans with common risk characteristics, in combination with the quantitative historical lifetime loss information and specific reserves, provides the Company with an estimate of lifetime losses.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The calculation of current expected credit losses is inherently subjective, as it requires management to exercise judgment in determining appropriate factors used to determine the allowance. The estimated loan losses for all loan pools are adjusted for changes in qualitative factors not inherently considered in the quantitative analyses to bring the allowance to the level management believes is appropriate based on factors that have not otherwise been fully accounted for, including adjustments for foresight risk, input imprecision and model imprecision. The qualitative categories and the measurements used to quantify the risks within each of these categories are subjectively selected by management, but measured by objective measurements period over period. The data for each measurement may be obtained from internal or external sources. The current period measurements are evaluated and assigned a factor commensurate with the current level of risk relative to past measurements over time. The resulting qualitative adjustments are applied to the relevant collectively evaluated loan portfolios. These adjustments are based upon quarterly trend assessments in portfolio concentrations, changes in lending policies and procedures, policy exceptions, independent loan review results, internal risk ratings and peer group credit quality trends. The qualitative allowance allocation, as determined by the processes noted above, is increased or decreased for each loan pool based on the assessment of these various qualitative factors. The determination of the appropriate qualitative adjustment is based on management's analysis of current and expected economic conditions and their impact to the portfolio, as well as internal credit risk movements and a qualitative assessment of the lending environment, including underwriting standards. Management recognizes the sensitivity of various assumptions made in the quantitative modeling of expected losses and may adjust reserves depending upon the level of uncertainty that currently exists in one or more assumptions.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">While policies and procedures used to estimate the allowance for credit losses on loans, as well as the resultant provision for credit losses charged to income, are considered adequate by management and are reviewed periodically by regulators and internal audit, they are approximate and could materially change based on changes within the loan portfolio and effects from economic factors. There are factors beyond the Company’s control, such as changes in projected economic conditions, including political instability or global events affecting the U.S. economy, real estate markets or particular industry conditions which could cause changes to expectations for current conditions and economic forecasts that could result in an unanticipated increase in the allowance and may materially impact asset quality and the adequacy of the allowance for credit losses and thus the resulting provision for credit losses. </span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In assessing the adequacy of the allowance for credit losses on loans, the Company considers the results of its ongoing independent loan review process. The Company undertakes this process both to ascertain those loans in the portfolio with elevated credit risk and to assist in its overall evaluation of the risk characteristics of the entire loan portfolio. Its loan review process includes the judgment of management, independent internal loan reviewers and reviews that may have been conducted by third-party reviewers including regulatory examiners. The Company incorporates relevant loan review results in the allowance.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In accordance with CECL, losses are estimated over the remaining contractual terms of loans, adjusted for prepayments. The contractual term excludes expected extensions, renewals and modifications unless management has a reasonable expectation at the reporting date that a troubled debt restructuring will be executed or such renewals, extensions or modifications are included in the original loan agreement and are not unconditionally cancellable by the Company.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Credit losses are estimated on the amortized cost basis of loans, which includes the principal balance outstanding, purchase discounts and premiums and deferred loan fees and costs. Loan losses are not estimated for accrued interest receivable as interest that is deemed uncollectible is written off through interest income in a timely manner. Accrued interest is presented separately on the balance sheets and as allowed under ASC Topic 326 is excluded from the tabular loan disclosures in Note 6 – Loans and Allowance for Credit Losses.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Allowance for Credit Losses on Unfunded Commitments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company estimates expected credit losses over the contractual term in which the Company is exposed to credit risk through a contractual obligation to extend credit, unless the obligation is unconditionally cancellable by the Company. The allowance for credit losses on unfunded commitments is adjusted as a provision for (or reversal of) credit loss expense. The estimates are determined based on the likelihood of funding during the contractual term and an estimate of credit losses subsequent to funding. Estimated credit losses on subsequently funded balances are based on the same assumptions as used to estimate credit losses on existing funded loans. </span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Allowance for Credit Losses - Securities Available for Sale</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For securities classified as available for sale that are in an unrealized loss position at the balance sheet date, the Company first assesses whether or not it intends to sell the security, or more likely than not will be required to sell the security, before recovery of its amortized cost basis. If either criteria is met, the security's amortized cost basis is written down to fair value through net income. If neither criteria is met, the Company evaluates whether any portion of the decline in fair value is the result of credit deterioration. Such evaluations consider the extent to which the amortized cost of the security exceeds its fair value, changes in credit ratings and any other known adverse conditions related to the specific security. If the evaluation indicates that a credit loss exists, an allowance for credit losses is recorded through provisions for credit losses for the amount by which the amortized cost basis of the security exceeds the present value of cash flows expected to be collected, limited by the amount by which the amortized cost exceeds fair value. Losses are charged against the allowance when management believes the uncollectibility of an available for sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. Any impairment not recognized in the allowance for credit losses is recognized in other comprehensive income. For certain types of debt securities, such as U.S. Treasuries and other securities with government guarantees, entities may expect zero credit losses. The zero-loss expectation applies to all of the Company’s securities and no allowance for credit losses was recorded on its available for sale securities portfolio at transition.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Prior to the adoption of ASU 2016-13, declines in the fair value of available-for-sale securities below their cost that were deemed to be other than temporary were reflected in earnings as realized losses. In estimating other-than-temporary impairment losses prior to January 1, 2020, management considered, among other things, (i) the length of time and the extent to which the fair value had been less than cost, (ii) the financial condition and near-term prospects of the issuer and (iii) the intent and our ability to retain our investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value.</span></div><div style="margin-top:12pt;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Accrued interest receivable on available for sale securities totaled $7.4 million at December 31, 2021 and is excluded from the estimate of credit losses.</span></div>
CY2021Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	7400000	USD
CY2019Q1	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	15300000	USD
CY2019Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	15700000	USD
CY2021	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	1	Segment
CY2021Q4	us-gaap	Other Real Estate OtherRealEstate	0	USD
CY2021	abtx	Percentage Of Tax Benefit Realized Upon Ultimate Settlement With Taxing Authority PercentageOfTaxBenefitRealizedUponUltimateSettlementWithTaxingAuthority	0.50
CY2021	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Reclassifications</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">—Some items in the prior year financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior year net income or shareholders’ equity.</span>
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	34663000	USD
CY2020Q1	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3866000	USD
CY2021Q4	abtx	Merger Shares Consideration Received Ratio MergerSharesConsiderationReceivedRatio	1.4184	shares
CY2018Q4	us-gaap	Goodwill Goodwill	223125000	USD
CY2019	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	-61000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	223642000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	223642000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	223642000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	3003000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	2323000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	2188000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	2061000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1941000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	3142000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	14658000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	1750663000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	37920000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	14818000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	1773765000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	728043000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	45177000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	330000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	772890000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	6510000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	6622000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	257736000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	257368000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	146510000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	151324000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	589533000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	614799000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	1000289000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	1030113000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	750374000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	743652000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	1750663000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	1773765000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	996300000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	13302000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	45882000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	1516000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	1042182000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	14818000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	65083000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	294000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	4203000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	36000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	69286000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	330000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	4900000	USD
CY2021	abtx	Proceeds From Maturities Calls Of Available For Sale Securities ProceedsFromMaturitiesCallsOfAvailableForSaleSecurities	965000	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	49000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	30800000	USD
CY2020	abtx	Proceeds From Maturities Calls Of Available For Sale Securities ProceedsFromMaturitiesCallsOfAvailableForSaleSecurities	7300000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	391000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	104000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	287000	USD
CY2021Q4	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	258800000	USD
CY2020Q4	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	18500000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4220486000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4491764000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	47940000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	53173000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4172546000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4438591000	USD
CY2021Q4	abtx	Owner Occupied Loans To Commercial Real Estate Loans OwnerOccupiedLoansToCommercialRealEstateLoans	0.546
CY2021	abtx	Loans Amount To Appraised Value LoansAmountToAppraisedValue	0.90
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1183000	USD
CY2021	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	245000	USD
CY2021	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	175000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1253000	USD
CY2021Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	26000000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	3141000	USD
CY2020Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	34500000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	24127000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4220486000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28893000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4491764000	USD
CY2021	abtx	Financing Receivable Nonaccrual Interest Income Under Original Loan Terms FinancingReceivableNonaccrualInterestIncomeUnderOriginalLoanTerms	948000	USD
CY2020	abtx	Financing Receivable Nonaccrual Interest Income Under Original Loan Terms FinancingReceivableNonaccrualInterestIncomeUnderOriginalLoanTerms	902000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	1768855000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	878579000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	438572000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	274147000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	248643000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	162209000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	444398000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	5083000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4220486000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4491764000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	53173000	USD
CY2021	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-2923000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2481000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	171000	USD
CY2021	abtx	Financing Receivable Allowance For Credit Loss Net Write Off Recovery FinancingReceivableAllowanceForCreditLossNetWriteOffRecovery	-2310000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	47940000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	29438000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	26543000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	8583000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	550000	USD
CY2020	abtx	Financing Receivable Allowance For Credit Loss Net Write Off Recovery FinancingReceivableAllowanceForCreditLossNetWriteOffRecovery	-8033000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	53173000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	26331000	USD
CY2019	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	5939000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	309000	USD
CY2021	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	0	USD
CY2020	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	0	USD
CY2019	abtx	Financing Receivable Allowance For Credit Loss Net Write Off Recovery FinancingReceivableAllowanceForCreditLossNetWriteOffRecovery	-2832000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	29438000	USD
CY2021Q4	abtx	Off Balance Sheet Credit Loss Liability Allowance For Credit Loss OffBalanceSheetCreditLossLiabilityAllowanceForCreditLoss	5300000	USD
CY2020Q4	abtx	Off Balance Sheet Credit Loss Liability Allowance For Credit Loss OffBalanceSheetCreditLossLiabilityAllowanceForCreditLoss	4700000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3866000	USD
CY2020	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	831000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	4697000	USD
CY2021	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	601000	USD
CY2021Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	5298000	USD
CY2021Q4	abtx	Financing Receivable Excluding Accrued Interest Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Collateral Dependent FinancingReceivableExcludingAccruedInterestFinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossCollateralDependent	16568000	USD
CY2020Q4	abtx	Financing Receivable Excluding Accrued Interest Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Collateral Dependent FinancingReceivableExcludingAccruedInterestFinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossCollateralDependent	8683000	USD
CY2021Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	13387000	USD
CY2021Q4	abtx	Financing Receivable Nonaccrual With Related Allowance FinancingReceivableNonaccrualWithRelatedAllowance	10740000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	24127000	USD
CY2020Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	15194000	USD
CY2020Q4	abtx	Financing Receivable Nonaccrual With Related Allowance FinancingReceivableNonaccrualWithRelatedAllowance	13699000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28893000	USD
CY2021Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	19200000	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	25800000	USD
CY2021Q4	abtx	Financing Receivable Troubled Debt Restructuring Allowance For Credit Loss FinancingReceivableTroubledDebtRestructuringAllowanceForCreditLoss	1900000	USD
CY2020Q4	abtx	Financing Receivable Troubled Debt Restructuring Allowance For Credit Loss FinancingReceivableTroubledDebtRestructuringAllowanceForCreditLoss	3300000	USD
CY2021	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	10	contract
CY2021	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	3436000	USD
CY2021	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	3436000	USD
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	32	contract
CY2020	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	11804000	USD
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	11804000	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	17	contract
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	10196000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11610000	USD
CY2019	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	5100000	USD
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	5100000	USD
CY2021	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	620000	USD
CY2020	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	3200000	USD
CY2019	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	251000	USD
CY2021	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	3	contract
CY2021	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	247000	USD
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	4	contract
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	2600000	USD
CY2021	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	3400000	USD
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	11800000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4220486000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	10370000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	11850000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	83650000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	87318000	USD
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	19942000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	16633000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	63708000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	70685000	USD
CY2021	us-gaap	Depreciation Depreciation	4300000	USD
CY2020	us-gaap	Depreciation Depreciation	3700000	USD
CY2021	abtx	Number Of Leased Branch Locations And Office Space Along With Equipment NumberOfLeasedBranchLocationsAndOfficeSpaceAlongWithEquipment	16	branchLocationAndOfficeSpace
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y11M19D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y6M21D
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0262
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0286
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	3471000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	3270000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	3073000	USD
CY2021	us-gaap	Short Term Lease Cost ShortTermLeaseCost	34000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	78000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	553000	USD
CY2021	us-gaap	Sublease Income SubleaseIncome	72000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	66000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	72000	USD
CY2021	us-gaap	Lease Cost LeaseCost	3433000	USD
CY2020	us-gaap	Lease Cost LeaseCost	3282000	USD
CY2019	us-gaap	Lease Cost LeaseCost	3554000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	2951000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	3068000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	2350000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	2664000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1892000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	2056000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1366000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1591000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	894000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	1057000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	1594000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	2355000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	11047000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	12791000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	677000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	941000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	10370000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	11850000	USD
CY2021Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	707500000	USD
CY2020Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	726800000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	986726000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	184807000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	61661000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	26338000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	31293000	USD
CY2021Q4	us-gaap	Time Deposits TimeDeposits	1290825000	USD
CY2021Q4	us-gaap	Interest Bearing Domestic Deposit Brokered InterestBearingDomesticDepositBrokered	306400000	USD
CY2020Q4	us-gaap	Interest Bearing Domestic Deposit Brokered InterestBearingDomesticDepositBrokered	453800000	USD
CY2021Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	16300000	USD
CY2020Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	9200000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	2783000	USD
CY2021Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	11341000	USD
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	15558000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	17527000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	13514000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-7090000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-87000	USD
CY2021	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	18341000	USD
CY2020	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	10437000	USD
CY2019	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	13427000	USD
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	20978000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	11754000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	13940000	USD
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-620000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	136000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-11000	USD
CY2021	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	2190000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1475000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	698000	USD
CY2021	abtx	Effective Income Tax Rate Reconciliation Merger Expense EffectiveIncomeTaxRateReconciliationMergerExpense	227000	USD
CY2020	abtx	Effective Income Tax Rate Reconciliation Merger Expense EffectiveIncomeTaxRateReconciliationMergerExpense	0	USD
CY2019	abtx	Effective Income Tax Rate Reconciliation Merger Expense EffectiveIncomeTaxRateReconciliationMergerExpense	0	USD
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-54000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	22000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	196000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18341000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10437000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	13427000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	11240000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	12590000	USD
CY2021Q4	abtx	Deferred Tax Assets Deferred Loan Fees DeferredTaxAssetsDeferredLoanFees	1077000	USD
CY2020Q4	abtx	Deferred Tax Assets Deferred Loan Fees DeferredTaxAssetsDeferredLoanFees	3164000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	836000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	655000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Hedging Transactions DeferredTaxAssetsHedgingTransactions	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Hedging Transactions DeferredTaxAssetsHedgingTransactions	263000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	216000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	342000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	13369000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	17014000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	3416000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	3964000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	4853000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	9417000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2551000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2573000	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	10820000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	15954000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	2549000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	1060000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
CY2021	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
CY2021	abtx	Number Of Stock Based Employee Compensation Plans NumberOfStockBasedEmployeeCompensationPlans	2	compensationPlan
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	3200000	shares
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	4000000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3400000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3100000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	616000	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	19.90
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	10904000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	141000	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	15.72
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	6000	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	20.36
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	469000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	21.08
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y5M4D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	6118000	USD
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2021	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	185000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	18.35
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	1000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	34.14
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	283000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	22.74
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y10M24D
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	5508000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	282000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	22.66
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y10M17D
CY2021Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	5506000	USD
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	3003000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	734000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	751000	USD
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	3372000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	2221000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	2709000	USD
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	0
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	0
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	0
CY2021Q4	abtx	Offbalance Sheet Financial Instrument Fixed Rate Contractual Amount OffbalanceSheetFinancialInstrumentFixedRateContractualAmount	492977000	USD
CY2021Q4	abtx	Offbalance Sheet Financial Instrument Variable Rate Contractual Amount OffbalanceSheetFinancialInstrumentVariableRateContractualAmount	619730000	USD
CY2020Q4	abtx	Offbalance Sheet Financial Instrument Fixed Rate Contractual Amount OffbalanceSheetFinancialInstrumentFixedRateContractualAmount	361030000	USD
CY2020Q4	abtx	Offbalance Sheet Financial Instrument Variable Rate Contractual Amount OffbalanceSheetFinancialInstrumentVariableRateContractualAmount	488070000	USD
CY2021Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	1360000000	USD
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	410200000	USD
CY2021	abtx	Commitments To Make Loans Period CommitmentsToMakeLoansPeriod	P120D
CY2021Q4	us-gaap	Capital Capital	722010000	USD
CY2021Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1608
CY2021Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	359214000	USD
CY2021Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2021Q4	us-gaap	Excess Capital ExcessCapital	471468000	USD
CY2021Q4	us-gaap	Excess Capital To Risk Weighted Assets ExcessCapitalToRiskWeightedAssets	0.1050
CY2021Q4	abtx	Common Equity Tier One Risk Based Capital CommonEquityTierOneRiskBasedCapital	559926000	USD
CY2021Q4	abtx	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.1247
CY2021Q4	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacy	202058000	USD
CY2021Q4	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeighted	0.0450
CY2021Q4	abtx	Excess Common Equity Tier One Risk Based Capital ExcessCommonEquityTierOneRiskBasedCapital	314312000	USD
CY2021Q4	abtx	Excess Common Equity Tier One Risk Based Capitalto Risk Weighted Assets ExcessCommonEquityTierOneRiskBasedCapitaltoRiskWeightedAssets	0.0700
CY2021Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	569678000	USD
CY2021Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1269
CY2021Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	269410000	USD
CY2021Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2021Q4	us-gaap	Excess Tier One Risk Based Capital ExcessTierOneRiskBasedCapital	381665000	USD
CY2021Q4	us-gaap	Excess Tier One Risk Based Capital To Risk Weighted Assets ExcessTierOneRiskBasedCapitalToRiskWeightedAssets	0.0850
CY2021Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	569678000	USD
CY2021Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0853
CY2021Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	267286000	USD
CY2021Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2021Q4	us-gaap	Excess Tier One Leverage Capital ExcessTierOneLeverageCapital	267286000	USD
CY2021Q4	us-gaap	Excess Tier One Leverage Capital To Average Assets ExcessTierOneLeverageCapitalToAverageAssets	0.0400
CY2020Q4	us-gaap	Capital Capital	642155000	USD
CY2020Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1571
CY2020Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	327084000	USD
CY2020Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2020Q4	us-gaap	Excess Capital ExcessCapital	429298000	USD
CY2020Q4	us-gaap	Excess Capital To Risk Weighted Assets ExcessCapitalToRiskWeightedAssets	0.1050
CY2020Q4	abtx	Common Equity Tier One Risk Based Capital CommonEquityTierOneRiskBasedCapital	482643000	USD
CY2020Q4	abtx	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.1180
CY2020Q4	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacy	183985000	USD
CY2020Q4	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeighted	0.0450
CY2020Q4	abtx	Excess Common Equity Tier One Risk Based Capital ExcessCommonEquityTierOneRiskBasedCapital	286199000	USD
CY2020Q4	abtx	Excess Common Equity Tier One Risk Based Capitalto Risk Weighted Assets ExcessCommonEquityTierOneRiskBasedCapitaltoRiskWeightedAssets	0.0700
CY2020Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	492281000	USD
CY2020Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1204
CY2020Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	245313000	USD
CY2020Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2020Q4	us-gaap	Excess Tier One Risk Based Capital ExcessTierOneRiskBasedCapital	347527000	USD
CY2020Q4	us-gaap	Excess Tier One Risk Based Capital To Risk Weighted Assets ExcessTierOneRiskBasedCapitalToRiskWeightedAssets	0.0850
CY2020Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	492281000	USD
CY2020Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0851
CY2020Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	231518000	USD
CY2020Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2020Q4	us-gaap	Excess Tier One Leverage Capital ExcessTierOneLeverageCapital	231518000	USD
CY2020Q4	us-gaap	Excess Tier One Leverage Capital To Average Assets ExcessTierOneLeverageCapitalToAverageAssets	0.0400
CY2021	us-gaap	Net Income Loss NetIncomeLoss	81553000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	45534000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	52959000	USD
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20206000	shares
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.04
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20415000	shares
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.23
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	21152000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.50
CY2021	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	149000	shares
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	131000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	272000	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20355000	shares
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.01
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20546000	shares
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.22
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	21424000	shares
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.47

Files In Submission

Name	View Source	Status
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Allegiance Bancshares, Inc.

2021 Form 10-K Financial Statement

#000164208122000007 Filed on February 25, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission