Allegiance Bancshares, Inc.

$ Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-Q Financial Statement

#000164208121000007 Filed on October 28, 2021

Income Statement

Concept	2021 Q4	2021 Q3	2020 Q3

Balance Sheet

Concept	2021 Q4	2021 Q3	2020 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$757.5M	$903.8M	$347.1M
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	$63.71M	$65.14M	$69.90M
YoY Change	-9.87%	-6.81%	4.02%
Goodwill	$223.6M	$223.6M	$223.6M
YoY Change	0.0%	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	$6.760B	$5.968B
YoY Change	17.43%	13.27%	21.65%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$1.800M	$3.300M	$3.100M
YoY Change	-33.33%	6.45%	-36.73%
Accrued Expenses	$10.40M	$11.10M	$11.70M
YoY Change	-12.61%	-5.13%	-3.31%
Deferred Revenue
YoY Change
Short-Term Debt
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$12.20M	$14.40M	$14.80M
YoY Change	-16.44%	-2.7%	-12.94%
LONG-TERM LIABILITIES
Long-Term Debt	$198.8M	$248.7M	$263.7M
YoY Change	-24.64%	-5.69%	-1.35%
Other Long-Term Liabilities	$29.90M	$31.20M	$18.80M
YoY Change	21.54%	65.96%	6.21%
Total Long-Term Liabilities	$228.7M	$279.9M	$282.5M
YoY Change	-20.7%	-0.92%	-0.88%
TOTAL LIABILITIES
Total Short-Term Liabilities	$12.20M	$14.40M	$14.80M
Total Long-Term Liabilities	$228.7M	$279.9M	$282.5M
Total Liabilities	$6.288B	$5.961B	$5.215B
YoY Change	18.84%	14.31%	24.17%
SHAREHOLDERS EQUITY
Retained Earnings	$267.1M	$248.0M
YoY Change	36.8%
Common Stock	$20.34M	$20.22M
YoY Change	0.64%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$816.5M	$798.6M	$753.1M
YoY Change
Total Liabilities & Shareholders Equity	$7.105B	$6.760B	$5.968B
YoY Change	17.43%	13.27%	21.65%

Cashflow Statement

Concept	2021 Q4	2021 Q3	2020 Q3

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0001642081
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Amendment Flag AmendmentFlag	false
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	us-gaap:PropertyPlantAndEquipmentNet
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	us-gaap:PropertyPlantAndEquipmentNet
CY2021Q3	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	us-gaap:OtherLiabilities
CY2020Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	us-gaap:OtherLiabilities
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2021-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-37585
	dei	Entity Registrant Name EntityRegistrantName	Allegiance Bancshares, Inc.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	TX
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	26-3564100
	dei	Entity Address Address Line1 EntityAddressAddressLine1	8847 West Sam Houston Parkway, N.
	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 200
	dei	Entity Address City Or Town EntityAddressCityOrTown	Houston
	dei	Entity Address State Or Province EntityAddressStateOrProvince	TX
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	77040
	dei	City Area Code CityAreaCode	281
	dei	Local Phone Number LocalPhoneNumber	894-3200
	dei	Security12b Title Security12bTitle	Common Stock, par value, $1.00 per share
	dei	Trading Symbol TradingSymbol	ABTX
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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	us-gaap	Other Noninterest Expense OtherNoninterestExpense	8601000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6750000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	34296000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	32565000	USD
	us-gaap	Noninterest Expense NoninterestExpense	102810000	USD
	us-gaap	Noninterest Expense NoninterestExpense	94745000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	23674000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	19847000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	73503000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	36167000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4614000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3677000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	13508000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6574000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	19060000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	16170000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	59995000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	29593000	USD
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.94
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.79
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.97
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.45
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.93
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.79
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.95
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.44
CY2021Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.12
CY2020Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.10
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.36
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.30
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	19060000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	16170000	USD
	us-gaap	Net Income Loss NetIncomeLoss	59995000	USD
	us-gaap	Net Income Loss NetIncomeLoss	29593000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-10548000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	2004000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-16356000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	33036000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	0	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	49000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	287000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	80000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	1477000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	-1495000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	225000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-10548000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	2084000	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-15153000	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	31254000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-2214000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	437000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-3182000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	6563000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-11971000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-8334000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1647000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	24691000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	10726000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	17817000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	48024000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	54284000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	736143000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	16170000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	1647000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.10
CY2020Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	2027000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	257000	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	863000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	753053000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	789150000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	19060000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8334000	USD
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.12
CY2021Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	2427000	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	111000	USD
CY2021Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1032000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	798592000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	709865000	USD
	us-gaap	Net Income Loss NetIncomeLoss	29593000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	24691000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.30
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6102000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	1727000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	9302000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2581000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	753053000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	758669000	USD
	us-gaap	Net Income Loss NetIncomeLoss	59995000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11971000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.36
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	7265000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	1932000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	5659000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2891000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	798592000	USD
	us-gaap	Net Income Loss NetIncomeLoss	59995000	USD
	us-gaap	Net Income Loss NetIncomeLoss	29593000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	5623000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	5666000	USD
	abtx	Recapture Of Provision For Credit Losses RecaptureOfProvisionForCreditLosses	255000	USD
	abtx	Recapture Of Provision For Credit Losses RecaptureOfProvisionForCreditLosses	23006000	USD
	abtx	Proceeds From Sales And Calls Of Available For Sale Securities ProceedsFromSalesAndCallsOfAvailableForSaleSecurities	4898000	USD
	abtx	Proceeds From Sales And Calls Of Available For Sale Securities ProceedsFromSalesAndCallsOfAvailableForSaleSecurities	30790000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	434000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5123000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-5295000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2498000	USD
	abtx	Excess Tax Benefit From Stock Based Compensation ExcessTaxBenefitFromStockBasedCompensation	262000	USD
	abtx	Excess Tax Benefit From Stock Based Compensation ExcessTaxBenefitFromStockBasedCompensation	65000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	415000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	438000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Loans AccretionAmortizationOfDiscountsAndPremiumsLoans	385000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Loans AccretionAmortizationOfDiscountsAndPremiumsLoans	2227000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Subordinated Debt AccretionAmortizationOfDiscountsAndPremiumsSubordinatedDebt	-86000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Subordinated Debt AccretionAmortizationOfDiscountsAndPremiumsSubordinatedDebt	-84000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Certificates Of Deposit AccretionAmortizationOfDiscountsAndPremiumsCertificatesOfDeposit	122000	USD
	abtx	Accretion Amortization Of Discounts And Premiums Certificates Of Deposit AccretionAmortizationOfDiscountsAndPremiumsCertificatesOfDeposit	295000	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-176000	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-258000	USD
	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	1317000	USD
	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	4065000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	49000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	287000	USD
	abtx	Federal Home Loan Bank Stock Dividends FederalHomeLoanBankStockDividends	52000	USD
	abtx	Federal Home Loan Bank Stock Dividends FederalHomeLoanBankStockDividends	170000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2891000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2581000	USD
	abtx	Increase Decrease In Operating Leases IncreaseDecreaseInOperatingLeases	2155000	USD
	abtx	Increase Decrease In Operating Leases IncreaseDecreaseInOperatingLeases	1947000	USD
	abtx	Increase Decrease In Accrued Interest Receivable And Other Assets IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets	2919000	USD
	abtx	Increase Decrease In Accrued Interest Receivable And Other Assets IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets	21070000	USD
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	7633000	USD
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	-2397000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	81656000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	37626000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3249803000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3548616000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	3714411000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	3839758000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	-209737000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	687460000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	2557000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	5520000	USD
	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	430000	USD
	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	4027000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	518000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	3304000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-252618000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-952609000	USD
	us-gaap	Net Change Noninterest Bearing Deposits Domestic NetChangeNoninterestBearingDepositsDomestic	382116000	USD
	us-gaap	Net Change Noninterest Bearing Deposits Domestic NetChangeNoninterestBearingDepositsDomestic	520468000	USD
	us-gaap	Net Change Interest Bearing Deposits Domestic NetChangeInterestBearingDepositsDomestic	296402000	USD
	us-gaap	Net Change Interest Bearing Deposits Domestic NetChangeInterestBearingDepositsDomestic	329092000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	0	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	65000000	USD
	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	-15569000	USD
	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	15000000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7265000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6102000	USD
	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	1932000	USD
	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	1727000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	5659000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	9302000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	651957000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	915883000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	480995000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	900000	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
CY2021Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	903761000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	347148000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	16250000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	5800000	USD
	us-gaap	Interest Paid Net InterestPaidNet	18498000	USD
	us-gaap	Interest Paid Net InterestPaidNet	32178000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	2596000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	2438000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1446000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	2221000	USD
	abtx	Loans Transferred To Other Real Estate LoansTransferredToOtherRealEstate	821000	USD
	abtx	Loans Transferred To Other Real Estate LoansTransferredToOtherRealEstate	539000	USD
	abtx	Bank Financed Sales Of Other Real Estate BankFinancedSalesOfOtherRealEstate	8125000	USD
	abtx	Bank Financed Sales Of Other Real Estate BankFinancedSalesOfOtherRealEstate	2315000	USD
CY2021Q3	abtx	Number Of Offices In Which Entity Operates NumberOfOfficesInWhichEntityOperates	27	office
CY2020Q1	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	34663000	USD
CY2020Q1	abtx	Allowance For Credit Losses On Unfunded Commitments AllowanceForCreditLossesOnUnfundedCommitments	3866000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	223642000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	223642000	USD
CY2021Q3	us-gaap	Goodwill Goodwill	223642000	USD
	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	824000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	3003000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	2323000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	2188000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	2061000	USD
CY2021Q3	abtx	Finite Lived Intangible Assets Amortization Expense After Year Four FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour	5083000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	15482000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1183034000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	37219000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	8777000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1211476000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	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	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	772890000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	3879000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	3939000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	13365000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	14012000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	136698000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	141890000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	547906000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	571041000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	701848000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	730882000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	481186000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	480594000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1183034000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1211476000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	436333000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	8136000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	26873000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	641000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	463206000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	8777000	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
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	4900000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	49000	USD
CY2021Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2020Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	30800000	USD
	abtx	Proceeds From Maturities Calls Of Available For Sale Securities ProceedsFromMaturitiesCallsOfAvailableForSaleSecurities	7100000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	391000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	104000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	287000	USD
CY2021Q3	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	11700000	USD
CY2020Q4	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	18500000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	4289469000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	4491764000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	50491000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	53173000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	11525000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28893000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	4238978000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	4438591000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Impaired Nonperforming Accrual Of Interest LoansAndLeasesReceivableImpairedNonperformingAccrualOfInterest	27400000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Accrual Of Interest LoansAndLeasesReceivableImpairedNonperformingAccrualOfInterest	34500000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	20795000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28369000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	4240305000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	4289469000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	4451346000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	4491764000	USD
CY2021Q3	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	1474952000	USD
CY2021Q3	us-gaap	Financing Receivable Originated In Fiscal Year Before Latest Fiscal Year FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear	1028850000	USD
CY2021Q3	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	499893000	USD
CY2021Q3	us-gaap	Financing Receivable Originated Three Years Before Latest Fiscal Year FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear	318981000	USD
CY2021Q3	us-gaap	Financing Receivable Originated Four Years Before Latest Fiscal Year FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear	279579000	USD
CY2021Q3	us-gaap	Financing Receivable Originated Five Or More Years Before Latest Fiscal Year FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear	225301000	USD
CY2021Q3	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	456424000	USD
CY2021Q3	us-gaap	Financing Receivable Revolving Converted To Term Loan FinancingReceivableRevolvingConvertedToTermLoan	5489000	USD
CY2021Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	4289469000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	4491764000	USD
CY2021Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	49586000	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1355000	USD
CY2021Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	527000	USD
CY2021Q3	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	77000	USD
CY2021Q3	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	450000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	50491000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	53173000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-1725000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	1111000	USD
	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	154000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	957000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	50491000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	47642000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1347000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	421000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	130000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	291000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	48698000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	29438000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	23006000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	4135000	USD
	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	389000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	3746000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	48698000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	10192000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	8683000	USD
CY2021Q3	abtx	Nonaccrual Loans With No Related Allowance NonaccrualLoansWithNoRelatedAllowance	16862000	USD
CY2021Q3	abtx	Nonaccrual Loans With Related Allowance NonaccrualLoansWithRelatedAllowance	11507000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28369000	USD
CY2020Q4	abtx	Nonaccrual Loans With No Related Allowance NonaccrualLoansWithNoRelatedAllowance	15194000	USD
CY2020Q4	abtx	Nonaccrual Loans With Related Allowance NonaccrualLoansWithRelatedAllowance	13699000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	28893000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	21400000	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	25800000	USD
CY2021Q3	abtx	Allowance For Credit Losses Change In Method Of Calculating Impairment1 AllowanceForCreditLossesChangeInMethodOfCalculatingImpairment1	2300000	USD
CY2020Q4	abtx	Allowance For Credit Losses Change In Method Of Calculating Impairment1 AllowanceForCreditLossesChangeInMethodOfCalculatingImpairment1	3300000	USD
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	8001000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	8001000	USD
	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	21000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	3	contract
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	247000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	contract
CY2021Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	4	contract
CY2021Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	300000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	300000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	9	contract
CY2020Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	4197000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	4197000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	8	contract
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	1650000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	1650000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	25	contract
	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	632000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	22000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	1700000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	8000000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	4289469000	USD
	abtx	Number Of Leased Branch Locations And Office Space NumberOfLeasedBranchLocationsAndOfficeSpace	16	lease
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	10901000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11610000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	11091000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	11850000	USD
CY2021Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y1M6D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y6M21D
CY2021Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0263
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0286
CY2021Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	884000	USD
CY2020Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	839000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	2617000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	2422000	USD
CY2021Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	3000	USD
CY2020Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	14000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	34000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	64000	USD
CY2021Q3	us-gaap	Sublease Income SubleaseIncome	19000	USD
CY2020Q3	us-gaap	Sublease Income SubleaseIncome	18000	USD
	us-gaap	Sublease Income SubleaseIncome	55000	USD
	us-gaap	Sublease Income SubleaseIncome	48000	USD
CY2021Q3	us-gaap	Lease Cost LeaseCost	868000	USD
CY2020Q3	us-gaap	Lease Cost LeaseCost	835000	USD
	us-gaap	Lease Cost LeaseCost	2596000	USD
	us-gaap	Lease Cost LeaseCost	2438000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	3173000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	3068000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	2388000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	2664000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	2097000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	2056000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1400000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1591000	USD
CY2020Q4	us-gaap	Deposits Fair Value Disclosure DepositsFairValueDisclosure	4988482000	USD
CY2020Q4	us-gaap	Interest Rate Derivative Liabilities At Fair Value InterestRateDerivativeLiabilitiesAtFairValue	1252000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1020000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1057000	USD
CY2021Q3	abtx	Lessee Operating Lease Liability To Be Paid After Year Four LesseeOperatingLeaseLiabilityToBePaidAfterYearFour	1759000	USD
CY2020Q4	abtx	Lessee Operating Lease Liability To Be Paid After Year Four LesseeOperatingLeaseLiabilityToBePaidAfterYearFour	2355000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	11837000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	12791000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	746000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	941000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	11091000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	11850000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	422766000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	772890000	USD
CY2020Q4	abtx	Loans Held For Investment Net Of Allowance Fair Value LoansHeldForInvestmentNetOfAllowanceFairValue	4438591000	USD
CY2020Q4	abtx	Accrued Interest Receivable Fair Value AccruedInterestReceivableFairValue	40053000	USD
CY2020Q4	abtx	Accrued Interest Payable Fair Value AccruedInterestPayableFairValue	2701000	USD
CY2020Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	155515000	USD
CY2020Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	108322000	USD
CY2021Q3	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	250000	USD
CY2020Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	250000	USD
CY2021Q3	abtx	Time Deposits250000 Or More TimeDeposits250000OrMore	783300000	USD
CY2020Q4	abtx	Time Deposits250000 Or More TimeDeposits250000OrMore	726800000	USD
CY2021Q3	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	1017921000	USD
CY2021Q3	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	242059000	USD
CY2021Q3	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	61317000	USD
CY2021Q3	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	34594000	USD
CY2021Q3	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	25123000	USD
CY2021Q3	us-gaap	Time Deposits TimeDeposits	1381014000	USD
CY2021Q3	us-gaap	Interest Bearing Domestic Deposit Brokered InterestBearingDomesticDepositBrokered	303700000	USD
CY2020Q4	us-gaap	Interest Bearing Domestic Deposit Brokered InterestBearingDomesticDepositBrokered	453800000	USD
CY2021Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	11300000	USD
CY2021Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	11341000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4600000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	13500000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3700000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6600000	USD
CY2021Q3	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.195
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.184
CY2020Q3	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.185
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.182
CY2021Q3	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
	abtx	Number Of Stock Based Employee Compensation Plans NumberOfStockBasedEmployeeCompensationPlans	2	compensationPlan
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	3200000	shares
CY2021Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1000000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2900000	USD
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	863000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2600000	USD
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
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	109000	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	18.48
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	1000	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	37.55
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	359000	shares
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	21.77
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y11M15D
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	5865000	USD
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	361000	shares
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	21.61
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y11M15D
CY2021Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	5975000	USD
CY2021Q3	abtx	Offbalance Sheet Financial Instrument Fixed Rate Contractual Amount OffbalanceSheetFinancialInstrumentFixedRateContractualAmount	1097306000	USD
CY2021Q3	abtx	Offbalance Sheet Financial Instrument Variable Rate Contractual Amount OffbalanceSheetFinancialInstrumentVariableRateContractualAmount	554187000	USD
CY2020Q4	abtx	Offbalance Sheet Financial Instrument Fixed Rate Contractual Amount OffbalanceSheetFinancialInstrumentFixedRateContractualAmount	771190000	USD
CY2020Q4	abtx	Offbalance Sheet Financial Instrument Variable Rate Contractual Amount OffbalanceSheetFinancialInstrumentVariableRateContractualAmount	488070000	USD
	abtx	Commitments To Make Loans Period CommitmentsToMakeLoansPeriod	P120D
	abtx	Off Balance Sheet Fixed Rate Loan Commitments Weighted Average Maturity OffBalanceSheetFixedRateLoanCommitmentsWeightedAverageMaturity	P3Y8M19D
CY2020	abtx	Off Balance Sheet Fixed Rate Loan Commitments Weighted Average Maturity OffBalanceSheetFixedRateLoanCommitmentsWeightedAverageMaturity	P3Y6M10D
CY2021Q3	abtx	Capital Conservation Buffer CapitalConservationBuffer	0.025
CY2021Q3	us-gaap	Capital Capital	700013000	USD
CY2021Q3	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1613
CY2021Q3	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	347221000	USD
CY2021Q3	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2021Q3	us-gaap	Excess Capital ExcessCapital	455728000	USD
CY2021Q3	us-gaap	Excess Capital To Risk Weighted Assets ExcessCapitalToRiskWeightedAssets	0.1050
CY2021Q3	abtx	Common Equity Tier One Risk Based Capital CommonEquityTierOneRiskBasedCapital	537008000	USD
CY2021Q3	abtx	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.1237
CY2021Q3	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacy	195312000	USD
CY2021Q3	abtx	Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeighted	0.0450
CY2021Q3	abtx	Excess Common Equity Tier One Risk Based Capital ExcessCommonEquityTierOneRiskBasedCapital	303819000	USD
CY2021Q3	abtx	Excess Common Equity Tier One Risk Based Capitalto Risk Weighted Assets ExcessCommonEquityTierOneRiskBasedCapitaltoRiskWeightedAssets	0.0700
CY2021Q3	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	546732000	USD
CY2021Q3	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1260
CY2021Q3	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	260416000	USD
CY2021Q3	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2021Q3	us-gaap	Excess Tier One Risk Based Capital ExcessTierOneRiskBasedCapital	368923000	USD
CY2021Q3	us-gaap	Excess Tier One Risk Based Capital To Risk Weighted Assets ExcessTierOneRiskBasedCapitalToRiskWeightedAssets	0.0850
CY2021Q3	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	546732000	USD
CY2021Q3	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0876
CY2021Q3	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	249563000	USD
CY2021Q3	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2021Q3	us-gaap	Excess Tier One Leverage Capital ExcessTierOneLeverageCapital	249563000	USD
CY2021Q3	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
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	19060000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	16170000	USD
	us-gaap	Net Income Loss NetIncomeLoss	59995000	USD
	us-gaap	Net Income Loss NetIncomeLoss	29593000	USD
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20369000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20221000	shares
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.94
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20439000	shares
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.79
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20188000	shares
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.97
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	20421000	shares
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.45
CY2021Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	190000	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	93000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	181000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	130000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20411000	shares
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.93
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20532000	shares
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.79
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.95
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	20551000	shares
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.44
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	22800	shares

Files In Submission

Name	View Source	Status
0001642081-21-000007-index-headers.html	Edgar Link	pending
0001642081-21-000007-index.html	Edgar Link	pending
0001642081-21-000007.txt	Edgar Link	pending
0001642081-21-000007-xbrl.zip	Edgar Link	pending
abtx-20210930.htm	Edgar Link	pending
abtx-20210930.xsd	Edgar Link	pending
abtx-20210930x10qex311.htm	Edgar Link	pending
abtx-20210930x10qex312.htm	Edgar Link	pending
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abtx-20210930x10qex322.htm	Edgar Link	pending
abtx-20210930_cal.xml	Edgar Link	unprocessable
abtx-20210930_def.xml	Edgar Link	unprocessable
abtx-20210930_htm.xml	Edgar Link	completed
abtx-20210930_lab.xml	Edgar Link	unprocessable
abtx-20210930_pre.xml	Edgar Link	unprocessable
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
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Allegiance Bancshares, Inc.

2021 Q4 Form 10-Q Financial Statement

#000164208121000007 Filed on October 28, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission