Document And Entity Information
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Note To Financial Statement Details Textual
Significant Accounting Policies
us-gaap_InterestExpenseNegotiableOrderOfWithdrawalNOWDeposits
NOW accounts
Note 1 - Summary of Significant Accounting Policies
Note 3 - Debt and Equity Securities
Interest expense:
Financing Receivables, Period Past Due [Domain]
Note 4 - Loans Receivable and Credit Disclosures
Equity securities, Estimated fair value
Financing Receivables, Period Past Due [Axis]
2020, Weighted average interest rate
Note 5 - Bank Premises and Equipment
Note 6 - Other Real Estate Owned
Financing Receivables [Text Block]
Note 8 - Intangible Assets
Note 9 - Deposits
Debt securities, Estimated fair value
Note 10 - Pledged Collateral Related to Securities Sold Under Repurchase Agreements
2018, Weighted average interest rate
Past Due Financing Receivables [Table Text Block]
Note 11 - Borrowings
Note 13 - Income Taxes
Provision (credit) for off-balance sheet commitments
Amount of expense related to off-balance sheet commitments.
us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
Available-for-sale Securities Pledged as Collateral
Note 14 - Commitments, Contingencies and Concentrations of Credit Risk
us-gaap_InterestIncomeOperating
Interest
Note 15 - Regulatory Matters
Net (increase) in loans
Decrease in loans
The net change during the reporting period in the value of loans or securitized loans that are held in portfolio.
Note 16 - Fair Value Measurements
atlo_NetIncreaseDecreaseInInterestBearingDepositsInFinancialInstitutions
Net decrease (increase) in interest bearing deposits in financial institutions
The net cash inflow or outflow associated with interest bearing deposits in financial institutions.
us-gaap_InterestAndDividendIncomeOperating
Total interest income
Total interest income
Note 18 - Ames National Corporation (Parent Company Only) Financial Statements
Note 19 - Selected Quarterly Financial Data (Unaudited)
Note 1 - Summary of Significant Accounting Policies - Basic Earnings Per Share (EPS) (Details)
Estimated fair value
Securities available-for-sale
Available for sale securities
Note 3 - Debt and Equity Securities - Securities Available-for-sale (Details)
Note 3 - Debt and Equity Securities - Debt Securities Available-for-sale (Details)
Note 3 - Debt and Equity Securities - Proceeds, Gains and Losses From Securities Available-for-sale (Details)
Note 3 - Debt and Equity Securities - Securities Available-for-sale Continuous Unrealized Loss Position (Details)
Note 4 - Loans Receivable and Credit Disclosures - Composition of Loans Receivable (Details)
2020, Amount
Note 4 - Loans Receivable and Credit Disclosures - Changes in the Allowance for Loan Losses (Details)
Note 4 - Loans Receivable and Credit Disclosures - Activity in Allowance for Loan Losses (Details)
Note 4 - Loans Receivable and Credit Disclosures - Credit Risk Profile by Internally Assigned Grade (Details)
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds
Note 4 - Loans Receivable and Credit Disclosures - Credit Risk Profile Based on Payment Activity (Details)
Note 4 - Loans Receivable and Credit Disclosures - Impaired Loans (Details)
Note 4 - Loans Receivable and Credit Disclosures - Troubled Debt Restructurings (Details)
Note 4 - Loans Receivable and Credit Disclosures - Past Due Loans (Details)
Note 4 - Loans Receivable and Credit Disclosures - Loan Transactions With Related Parties (Details)
Note 5 - Bank Premises and Equipment - Major Classes of Bank Premises and Equipment (Details)
Note 6 - Other Real Estate Owned - Changes in Other Real Estate Owned (Details)
Total FHLB advances, Weighted average interest rate
Note 6 - Other Real Estate Owned - Components of Other Real Estate Owned (Details)
Note 8 - Intangible Assets - Intangible Assets (Details)
Note 8 - Intangible Assets - Estimated Remaining Amortization Expense on Intangible Assets on Core Deposits (Details)
Watch [Member]
A category of financing receivables considered to be on watch status.
Note 8 - Intangible Assets - Core Deposit Intangible Assets Activity (Details)
Note 9 - Deposits - Maturities of Time Deposits (Details)
CASH FLOWS FROM INVESTING ACTIVITIES
Note 9 - Deposits - Interest Expense on Deposits (Details)
Note 10 - Pledged Collateral Related to Securities Sold Under Repurchase Agreements - Pledged Collateral at Estimated Fair Value (Details)
Note 11 - Borrowings - FHLB Advances and Other Long-term Borrowings (Details)
Reported Value Measurement [Member]
Note 11 - Borrowings - FHLB Advances and Other Long-term Borrowings (Details) (Parentheticals)
Note 13 - Income Taxes - Components of Income Tax Expense (Details)
Taxable
Note 13 - Income Taxes - Income Tax Reconciliation (Details)
Note 13 - Income Taxes - Income Tax Reconciliation (Details) (Parentheticals)
Securities:
Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details)
Tax-exempt
Note 14 - Commitments, Contingencies and Concentrations of Credit Risk - Summary of Commitments (Details)
Equity Securities, Other [Member]
Ownership interest or right to acquire or dispose of ownership interest in corporations and other legal entities for which ownership interest is represented by shares other than financial industry common stock.
Note 15 - Regulatory Matters - Actual Capital Amounts and Ratios (Details)
Note 16 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details)
Note 16 - Fair Value Measurements - Assets Measured at Fair Value on a Nonrecurring Basis (Details)
Note 16 - Fair Value Measurements - Fair Value Quantitative Information (Details)
Loans, including fees
Note 16 - Fair Value Measurements - Estimated Fair Values of Financial Instruments (Details)
Note 18 - Ames National Corporation (Parent Company Only) Financial Statements - Condensed Balance Sheets (Details)
Note 18 - Ames National Corporation (Parent Company Only) Financial Statements - Condensed Statements of Income (Details)
Note 18 - Ames National Corporation (Parent Company Only) Financial Statements - Condensed Statements of Cash Flows (Details)
Note 19 - Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Unaudited) (Details)
Notes To Financial Statements
Notes To Financial Statements [Abstract]
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive income
Increase (decrease) in accrued expenses and other liabilities
Increase (decrease) in accrued expense and other liabilities
Quarterly Financial Information [Text Block]
Use of Estimates, Policy [Policy Text Block]
Common stock, shares outstanding (in shares)
New Accounting Pronouncements, Policy [Policy Text Block]
Reclassification, Policy [Policy Text Block]
Construction and Land Development [Member]
Property classified as construction and land development.
One to Four Family Residential Real Estate [Member]
Property classified as 1-4 family residential real estate.
Interest income:
atlo_FiniteTaxLivedIntangibleAssetUsefulLife
Finite Tax Lived Intangible Asset, Useful Life
Useful tax life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
atlo_CommonEquityTierOneCapitalConservationBuffer
Common Equity Tier One Capital Conservation Buffer
A capital conservation buffer, comprised of Common Equity Tier 1, is established above the regulatory minimum capital requirement.
Boone Bank and Trust [Member]
Boone Bank is an Iowa, state-chartered, FDIC insured commercial bank. It provides full service banking to businesses and residents within the Boone community and surrounding area. It is actively engaged in agricultural, consumer and commercial lending, including real estate, operating and equipment loans. It conducts business from its main office and a full service office, both located in Boone.
Consolidation, Policy [Policy Text Block]
Effective January 2019 [Member]
Represents regulations effective in January 2019.
First National Bank [Member]
First National is a nationally-chartered, commercial bank insured by the Federal Deposit Insurance Corporation (the "FDIC"). It provides full-service banking to businesses and residents within the Ames community and surrounding area. It provides a variety of products and services designed to meet the needs of the market it serves. First National conducts business out of three full-service offices, all located in the city of Ames and a full-service office in Ankeny, Iowa.
Also Conducts Business Out of 3 Full Service Offices in Des Moines Metro Area [Member]
In addition to First National Bank, also conducts business out of 3 full service offices in the Des Moines metro area.
Conducts Business Out of Offices at Story City, Garner, and Kleme, Iowa [Member]
Also conducts business out of three offices; Story City, Garner and Kleme, Iowa.
Reliance State Bank [Member]
The entity Reliance State Bank.
United Bank and Trust [Member]
United Bank is a nationally-chartered, commercial bank insured by the FDIC. It offers a broad range of deposit and loan products, as well as trust services to customers located in the Marshalltown and surrounding Marshall County area.
State Bank and Trust [Member]
State Bank is an Iowa, state-chartered, FDIC insured commercial bank. It provides full-service banking to businesses and residents within the Nevada area from its main Nevada location and one office in Colo, Iowa. It has a strong presence in agricultural, commercial and residential real estate lending.
us-gaap_CashAndCashEquivalentsAtCarryingValue
Beginning
Ending
us-gaap_DividendsCommonStockCash
Cash dividends declared
Subsequent Events [Text Block]
Common equity tier one risk based capital required for capital adequacy to risk weighted assets
The minimum Common Equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Cash and due from banks
Common equity tier one capital required to be well capitalized to risk weighted assets
The Common Equity Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.
Interest bearing deposits in financial institutions
Agriculture Real Estate [Member]
Segment of the company's total financing receivables related to agricultural real estate receivables
Family Residential Real Estate 1-4 [Member]
Segment of the company's total financing receivables related to 1-4 Family residential real estate.
Construction Real Estate [Member]
Segment of the company's total financing receivables related to construction real estate.
Consumer and Other [Member]
Segment of the company's total financing receivables related to consumer and other receivables.
Agriculture [Member]
Segment of the company's total financing receivables related to agriculture receivables.
Concentrations and Restrictions on Cash and Due from Banks and Interest Bearing Deposits in Financial Institutions [Text Block]
The entire disclosure of concentrations and restrictions on cash and due from bank and interest bearing deposits in financial institutions.
atlo_CashReserveRequirements
Cash Reserve Requirements
The Federal Reserve Bank requires member banks to maintain certain cash and due from bank reserves.
Debt Disclosure [Text Block]
Financing Receivables 30 to 89 Days Past Due [Member]
Financing receivables that are more than 29 days past due but fewer than 90 days past due.
Substandard Impaired [Member]
A category of financing receivables that are inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the creditor will sustain some loss if the deficiencies are not corrected. Also impaired.
Pension and Other Postretirement Benefits Disclosure [Text Block]
Credit Risk Profile Based on Payment Activity on Disaggregated Basis [Table Text Block]
Tabular disclosure of credit risk profile based on payment activity, on a disaggregated basis.
Other Real Estate Owned Roll Forward [Table Text Block]
Tabular disclosure of the change in other real estate on properties owned. Includes real estate assets taken in settlement of troubled loans through surrender or foreclosure by banks.
Loan and lease receivable other than consumer and residential
Element defines loans and lease receivable other than consumer and residential loans at book value.
Loan and lease receivable, consumer and residential
Element defines loans and lease receivable pertaining to consumer and residential loans at book value.
Transfer of loans
Value of other real estate transferred from the entity's loans to other real estate in noncash transactions.
Wealth Management Business [Member]
Represents information about wealth management business.
Schedule of Maturities of Time Deposits [Table Text Block]
Represents tabular disclosure of maturities of time deposits.
Valuation Technique [Domain]
us-gaap_IncreaseDecreaseInOtherOperatingAssets
(Increase) decrease in other assets
(Increase) decrease in other assets
Valuation Technique [Axis]
atlo_InterestExpenseMoneyMarketAccountsAndSavingsDeposits
Savings and money market
The aggregate interest expense incurred on the following for deposits in domestic offices: (1) money market deposits and (2) savings deposits.
Schedule of Interest Expense on Deposits [Table Text Block]
Represents tabular disclosure of interest expense on deposits.
2022
us-gaap_TimeDepositMaturitiesYearFive
Accrued income receivable
2019
us-gaap_TimeDepositMaturitiesYearTwo
2021
us-gaap_TimeDepositMaturitiesYearFour
2020
us-gaap_TimeDepositMaturitiesYearThree
2018
us-gaap_TimeDepositMaturitiesYearOne
atlo_PercentageOfLoanToValueRatiosMaximum
Percentage of Loan to Value Ratios, Maximum
This line item represents the maximum percentage of loan-to-value ratios without credit enhancements.
atlo_PercentageOfAppraisedValueOrPurchasePriceEntityLend
Percentage of Appraised Value or Purchase Price Entity Lend
Represents maximum percentage of appraised value or purchase price entity lend.
atlo_PerformingLoanRangeMaximum
Performing Loan Range, Maximum
Represents the maximum amount of performing loans. Performing loan is any loan in which: interest and principal payments are less than 90 days overdue; less than 90 days' worth of interest has been refinanced, capitalized, or delayed by agreement; and continued payment is anticipated.
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]
us-gaap_IncreaseDecreaseInInterestAndDividendsReceivable
(Increase) in accrued income receivable
(Increase) decrease in accrued income receivable
Ending balance: Individually evaluated for impairment
us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Schedule of Composition of Loans Receivable [Table Text Block]
Represents tabular disclosure of various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date.
Ending balance: Collectively evaluated for impairment
us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Schedule of Allowance for Loan Losses [Table Text Block]
Represents tabular disclosure for amount of allowances to cover probable credit losses on loans and leases.
Ending balance: Collectively evaluated for impairment
Ending balance: Individually evaluated for impairment
atlo_RentalIncomeOperating
Rental income
Income earned by providing the use of assets to an outside party in exchange for a payment or series of payments that is operating in nature.
Allowance for Credit Losses on Financing Receivables [Table Text Block]
Ending balance
Other real estate owned
Balance
Balance
Recoveries of loans charged-off
Time, $250,000 and over
Deposit Liabilities Disclosures [Text Block]
us-gaap_DeferredTaxAssetsValuationAllowance
Valuation allowance
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and stockholders' equity
Total liabilities and stockholders' equity
Retained earnings
Retained earnings
us-gaap_LoansAndLeasesReceivableAllowance
Allowance for loan losses
Balance
Balance
us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Loans charged-off
Loans receivable, net
us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Accumulated other comprehensive (loss)
Ending balance
Loans receivable
us-gaap_DeferredTaxAssetsNet
Deferred income taxes
us-gaap_LoansAndLeasesReceivableDeferredIncome
Deferred loan fees
atlo_OperatingIncomeLossBeforeProvisionForLoanLosses
The total for the period of operating income (loss) before provision for loan losses.
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
atlo_ProvisionCreditForLoanLosses
Credit for loan losses
Amount of expense (credit) related to estimated loss from loan transactions.
us-gaap_DeferredIncomeTaxLiabilities
Other noninterest income
us-gaap_DeferredTaxAssetsGross
atlo_OperatingIncomeLossAfterProvisionForLoanLosses
Operating income after credit for loan losses
The total for the period of operating income loss after provision for loan losses.
Schedule of Loan Transactions With Related Parties [Table Text Block]
Represents tabular disclosure of transactions pertaining to loans with related parties.
us-gaap_NoninterestIncome
Total noninterest income
Noninterest income
us-gaap_DeferredTaxAssetsLiabilitiesNet
Net deferred tax asset
us-gaap_DeferredTaxAssetsOther
Other deferred tax assets
Change in status
Reflects the amount of change in status to reduce the carrying amounts of loans and leases receivable due from them.
us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale
Originations of loans held for sale
Noninterest income:
us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss
Net interest income after provision for loan losses
Net interest income after provision for loan losses
Provision for loan losses
Provision for loan losses
us-gaap_NumberOfOperatingSegments
Number of Operating Segments
us-gaap_DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross
Net unrealized losses on securities available-for-sale
us-gaap_ProvisionForLoanLossesExpensed
Provision for loan losses
Proceeds from the sales of loans held for sale
us-gaap_InterestIncomeExpenseNet
Net interest income
Net interest income
Other intangible assets
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from other intangible assets.
atlo_PaymentsToAcquireOtherRealEstateAcquiredThroughForeclosures
Purchase of other real estate owned
The cash outflow associated with the purchase of other real estate acquired through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.
Other Real Estate Owned, Policy [Policy Text Block]
Disclosure of accounting policy for other real estate owned.
Accumulated other comprehensive (loss)
Trust Department Assets, Policy [Policy Text Block]
Disclosure of accounting policy for trust department assets.
Service fees
us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses
Allowance for loan losses
Segment Reporting, Policy [Policy Text Block]
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Fair Value, Measurements, Nonrecurring [Member]
Earnings Per Share, Policy [Policy Text Block]
Fair Value, Measurements, Recurring [Member]
Comprehensive Income, Policy [Policy Text Block]
Fair Value, Measurement Frequency [Domain]
Measurement Frequency [Axis]
Income Tax, Policy [Policy Text Block]
Change in assets and liabilities:
us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax
atlo_LiabilitiesToCoverCreditLossesForOffBalanceSheet
Liabilities to Cover Credit Losses for Off Balance Sheet
This line item represents liabilities to cover estimated credit losses for off-balance-sheet loan commitments and standby letters of credit.
Property, Plant and Equipment [Table Text Block]
atlo_FixedInterestRateCommitmentsToExtendCredit
Fixed Interest Rate, Commitments to Extend Credit
Represents fixed interest rate commitments to extend credit, as of balance sheet date.
us-gaap_InvestmentIncomeDividend
Dividends
Property, Plant and Equipment Disclosure [Text Block]
Deferred tax assets:
us-gaap_EquityMethodInvestmentDividendsOrDistributions
Dividends received from bank subsidiaries
us-gaap_DeferredTaxLiabilitiesOther
Other deferred tax liabilities
Provision for deferred income taxes
Provision for deferred income taxes
us-gaap_OtherOperatingIncome
Other income
Other intangible assets, net
Amendment Flag
FHLB advances
Common stock, $2 par value, authorized 18,000,000 shares; issued and outstanding 9,310,913 shares as of December 31, 2017 and 2016
Common stock
us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill
Goodwill
us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure
Common stock, shares authorized (in shares)
After
Common stock, shares issued (in shares)
2020
Common stock, par value (in dollars per share)
2019
2022
2021
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
atlo_DeferredTaxAssetsOtherRealEstateOwned
Other real estate owned
Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from other real estate owned.
Advertising Costs, Policy [Policy Text Block]
2018
Secured Borrowings [Text Block]
The entire disclosure for borrowings that are secured.
Current Fiscal Year End Date
Document Fiscal Period Focus
atlo_DeferredTaxAssetsAccruedVacation
Accrued vacation
Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from accrued vacation.
Document Fiscal Year Focus
Deferred tax liabilities:
Total FHLB and other borrowings, Amount
Federal Home Loan Bank Advances and Long Term Debt
This line item represents aggregate amount of federal home loan bank advances and long-term debt or borrowings.
Document Period End Date
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Bank premises and equipment
Total FHLB and other borrowings, Weighted average interest rate
This line item represents percentage of federal home loan bank advances and long term debt or borrowings.
Schedule of Maturities of Federal Home Loan Bank Advances and Long Term Debt [Table Text Block]
Tabular disclosure of maturities of federal home loan bank advances and long-term debt.
Document Type
Other comprehensive income (loss)
Other comprehensive income (loss), net of tax
Tax expense (benefit) related to other comprehensive income (loss)
Document Information [Line Items]
Document Information [Table]
us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent
Other comprehensive income (loss) before tax
Depreciation
Depreciation
Entity Public Float
Estimate of Fair Value Measurement [Member]
Entity Filer Category
Entity Current Reporting Status
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
Measurement Basis [Axis]
Portion at Fair Value Measurement [Member]
us-gaap_GainLossOnSaleOfLoansAndLeases
Gain on sales of loans held for sale
Deferred due to enacted changes in tax rates
us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations
us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit
Deferred
Intangible Assets Disclosure [Text Block]
Adjustments to reconcile net income to net cash provided by operating activities:
us-gaap_CurrentStateAndLocalTaxExpenseBenefit
Current
State:
Entity Central Index Key
us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations
Entity Registrant Name
us-gaap_DeferredFederalIncomeTaxExpenseBenefit
Deferred
Total
Estimated Fair Value
Entity [Domain]
Legal Entity [Axis]
us-gaap_CurrentFederalTaxExpenseBenefit
Current
Other real estate owned
us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure
Federal:
Unrealized holding gains (losses) arising during the period
Less: reclassification adjustment for gains realized in net income
us-gaap_LoansHeldForSaleFairValueDisclosure
Loans held for sale
Entity Common Stock, Shares Outstanding (in shares)
Income taxes
Additional paid-in capital
Additional paid-in capital
Interest
us-gaap_CashAndCashEquivalentsFairValueDisclosure
Cash and due from banks
STOCKHOLDERS' EQUITY
Wealth management income
Trading Symbol
Real Estate, Type of Property [Axis]
Real Estate [Domain]
Other comprehensive income (loss), before tax:
us-gaap_StockholdersEquity
Total stockholders' equity
Total stockholders' equity
Balance
Balance
atlo_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOffBalanceSheetReserves
Off balance sheet reserve
Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from off balance sheet reserves.
us-gaap_ProceedsFromIncomeTaxRefunds
Cash receipts for income taxes
us-gaap_Liabilities
Total liabilities
Total liabilities
US Treasury Securities [Member]
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]
US Government Agencies Debt Securities [Member]
Maturity Greater than 90 Days [Member]
us-gaap_DepositsFairValueDisclosure
Deposits
us-gaap_DepositsWithOtherFederalHomeLoanBanks
Deposits with Other Federal Home Loan Banks
CASH FLOWS FROM OPERATING ACTIVITIES
Maturity Overnight [Member]
us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability
Commitments
Repurchase Agreements and Similar Transactions, Maturity Periods [Axis]
Repurchase Agreements and Similar Transactions, Maturity Periods [Domain]
Statement [Line Items]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]
Repurchase Agreement, callable quarterly in 2018 and thereafter
Represents the quarterly callable amount for securities sold under repurchase agreements.
FDIC insurance assessments
Loans
us-gaap_LoansReceivableFairValueDisclosure
Accrued interest payable
Accrued expenses and other liabilities
Accrued expenses and other liabilities
us-gaap_NoninterestExpense
Total noninterest expense
Noninterest expense
Other operating expenses, net
AOCI Attributable to Parent [Member]
us-gaap_AccruedIncomeTaxes
Accrued Income Taxes
us-gaap_PropertyPlantAndEquipmentUsefulLife
Property, Plant and Equipment, Useful Life
Fair Value, by Balance Sheet Grouping [Table Text Block]
Commitments to Extend Credit [Member]
Fair Value Disclosures [Text Block]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]
ASSETS
Noninterest expense:
Furniture and Fixtures [Member]
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided by (used in) financing activities
Net cash used in financing activities
Net cash (used in) investing activities
Net cash used in investing activities
Building and Building Improvements [Member]
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by operating activities
Net cash provided by operating activities
us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
Net increase (decrease) in cash and due from banks
Net increase (decrease) in cash and cash equivalents
Building [Member]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Axis]
Land [Member]
Property, Plant and Equipment, Policy [Policy Text Block]
Business Acquisition, Acquiree [Domain]
Business Acquisition [Axis]
Transfers and Servicing of Financial Assets, Transfers of Financial Assets, Aggregation, Policy [Policy Text Block]
Total other borrowings, Amount
Other borrowings
us-gaap_PaymentsOfDividends
Dividends paid
Dividends paid
Financial Instruments [Domain]
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
2018, Amount
Financial Instrument [Axis]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 1 [Member]
Retained Earnings [Member]
Fair Value, Inputs, Level 3 [Member]
Additional Paid-in Capital [Member]
Fair Value Hierarchy [Domain]
Cash dividends declared, per share (in dollars per share)
Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block]
Fair Value, Hierarchy [Axis]
Off-Balance-Sheet Credit Exposure, Policy [Policy Text Block]
Equity Component [Domain]
Common Stock [Member]
Impaired financing receivable, related allowance
Loans, interest income recognized
Loans with an allowance recorded, interest income recognized
Equity Components [Axis]
Impaired financing receivable, recorded investment
Impaired financing receivable with related allowance, recorded investment
Loans with no specific reserve recorded, interest income recognized
Loans, average recorded investment
Loans with an allowance recorded, average recorded investment
Impaired financing receivable with no related allowance, recorded investment
Impaired financing receivable, unpaid principal balance
Impaired financing receivable with related allowance, unpaid principal balance
Other Liabilities [Member]
Loans with no specific reserve recorded, average recorded investment
Impaired financing receivable with no related allowance, unpaid principal balance
Goodwill Disclosure [Text Block]
Debt securities, Amortized cost
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax
Asset Class [Axis]
Asset Class [Domain]
Equity securities, Amortized cost
2018, Amount
us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
Weighted Average Number Diluted Shares Outstanding Adjustment
Basic and diluted earnings per share (in dollars per share)
Basic and diluted earnings per common share (in dollars per share)
us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross unrealized losses
Gross unrealized gains
us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued
Income Tax Examination, Penalties and Interest Accrued
Debt and Equity securities, Amortized cost
us-gaap_RepaymentsOfLongTermDebt
Payments on FHLB and other borrowings
Equipment [Member]
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable Portfolio Segment [Domain]
us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Total unrealized losses
Financing Receivable Portfolio Segment [Axis]
us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Less than 12 months, unrealized losses
us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
12 months or more, unrealized losses
Commercial Portfolio Segment [Member]
Weighted average common shares outstanding (in shares)
Balance Sheet Location [Domain]
Basic EPS (in dollars per share)
Balance Sheet Location [Axis]
Scenario, Unspecified [Domain]
Basic earning per share computation:
Scenario [Axis]
Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]
Proceeds from FHLB and other borrowings
12 months or more, estimated fair value
Other Real Estate Owned [Member]
Real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.
Less than 12 months, estimated fair value
Impaired Loan [Member]
A loan which is considered impaired.
Appraisal Valuation [Member]
The type or description of the valuation technique being used.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]
Total estimated fair value
Evaluation of Collateral [Member]
The type or description of the valuation technique use to determine the value of particular loans or assets.
Securities available for sale:
Receivables, Policy [Policy Text Block]
Unobservable Inputs, Rate
Percentage of estimation of value used as an input to measure fair value.
us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit
Interest bearing deposits
The fair value disclosure of interest bearing deposits.
Cash and Cash Equivalents, Policy [Policy Text Block]
Maximum [Member]
Range [Domain]
Weighted Average [Member]
Minimum [Member]
Significant Accounting Policies [Text Block]
Range [Axis]
us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits
Accounting Policies [Abstract]
Parent Company [Member]
Statement of Financial Position [Abstract]
Consolidated Entities [Domain]
Consolidated Entities [Axis]
Due after ten years, Estimated fair value
Tax provision applicable to net realized gains on securities available-for-sale
Element defines tax provision made during the period for realized gains on securities available for sale.
Due in one year or less, Estimated fair value
Due after five years through ten years, Estimated fair value
Condensed Cash Flow Statement [Table Text Block]
Due after one year through five years, Estimated fair value
Statement of Cash Flows [Abstract]
Securities sold under agreements to repurchase
Condensed Income Statement [Table Text Block]
Statement of Stockholders' Equity [Abstract]
us-gaap_Deposits
Total deposits
Condensed Balance Sheet [Table Text Block]
Due after ten years, Amortized cost
Due after five years through ten years, Amortized cost
Due after one year through five years, Amortized cost
Due in one year or less, Amortized cost
Quarterly Financial Information [Table Text Block]
Gross realized losses on securities available-for-sale
Demand, noninterest bearing
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Gross realized gains on securities available-for-sale
Investments Classified by Contractual Maturity Date [Table Text Block]
Realized Gain (Loss) on Investments [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Proceeds from sales of securities available-for-sale
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
NOW accounts
us-gaap_TimeDeposits
Schedule of Unrealized Loss on Investments [Table Text Block]
Finite-lived Intangible Assets Amortization Expense [Table Text Block]
Increase (decrease) in securities sold under agreements to repurchase
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]
Deposits
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
Fair Value Measurements, Nonrecurring [Table Text Block]
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Income before income taxes
Income before income taxes
Other time
Amount of time deposit liabilities, including certificates of deposit, in denominations of less than FDIC insurance limit.
us-gaap_IncomeLossFromEquityMethodInvestments
Equity in net income of bank subsidiaries
Equity in net income of bank subsidiaries
Provision for income taxes
Income tax expense
Income tax expense (benefit)
Dividends payable
Dividends payable
us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Increase in deposits
Corporate Debt Securities [Member]
US Treasury and Government [Member]
US States and Political Subdivisions Debt Securities [Member]
Major Types of Debt and Equity Securities [Domain]
Statement [Table]
Major Types of Debt and Equity Securities [Axis]
CASH FLOWS FROM FINANCING ACTIVITIES
Income Statement [Abstract]
us-gaap_PaymentsForProceedsFromOtherInvestingActivities
Other changes in other real estate owned
Class of Stock [Axis]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Core Deposits [Member]
Customer Lists [Member]
Collateral Related to Term Repurchase Agreements [Member]
Information related to term repurchase agreements of collateral.
Finite-Lived Intangible Assets, Major Class Name [Domain]
Collateral Related to Securities Sold Under Agreements to Repurchase [Member]
Information related to securities sold under an agreement to repurchase.
Special Mention [Member]
Finite-Lived Intangible Assets by Major Class [Axis]
Substandard [Member]
us-gaap_IncomeTaxReconciliationOtherAdjustments
Other
Income taxes, federal tax rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Securities gains, net
Securities gains, net
Securities gains
Securities gains, net
Effect of change in deferred tax asset related to enacted changes in tax rates
Gain on sale of loans held for sale
us-gaap_LoansAndLeasesReceivableRelatedParties
Balance
Balance
us-gaap_IncomeTaxReconciliationTaxExemptIncome
Tax-exempt interest and dividends
us-gaap_OperatingExpenses
Operating expenses
us-gaap_GoodwillPeriodIncreaseDecrease
Goodwill, Period Increase (Decrease)
Business development
us-gaap_LiabilityForUncertainTaxPositionsCurrent
Liability for Uncertainty in Income Taxes, Current
us-gaap_SecurityOwnedAndPledgedAsCollateralFairValue
Securities sold under agreements to repurchase
Salaries and employee benefits
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
State taxes, net of federal tax benefit
us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
Income taxes at 35% federal tax rate
Commitments and Contingencies Disclosure [Text Block]
Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block]
Financial Instruments Owned and Pledged as Collateral, Type [Domain]
Financial Instruments Owned and Pledged as Collateral by Type [Axis]
Income Tax Disclosure [Text Block]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Loss on sale and disposal of bank premises and equipment, net
Gain on sale, net
(Gain) on sale of other real estate owned, net
Gain on sale of other real estate owned
Gain on sale of other real estate owned
Proceeds from maturities and calls of securities available-for-sale
Proceeds from sale of securities available-for-sale
Proceeds from sale of securities available-for-sale
Other Real Estate, Roll Forward [Table Text Block]
Loans held for sale
Net proceeds from the sale of other real estate owned
Proceeds from the sale of other real estate owned
Pass [Member]
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life
Acquisition
Finite-lived Intangible Assets Acquired
Impairment of other real estate owned
Impairment
Internal Credit Assessment [Domain]
Internal Credit Assessment [Axis]
us-gaap_PaymentsToAcquireAvailableForSaleSecurities
Purchase of securities available-for-sale
Amortization of securities available-for-sale, loans and deposits, net
Amortization of intangible assets
Amortization of Intangible Assets
Amortization
Real Estate Owned [Text Block]
New loans
LIABILITIES
Professional fees
us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds
Repayments
us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Defined Contribution Plan, Employer Discretionary Contribution Amount
Proceeds from the sale or bank premises and equipment
us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans
LIABILITIES AND STOCKHOLDERS' EQUITY
Total assets
Total assets
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
Data processing
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent
us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Loans and Leases Receivable, Impaired, Commitment to Lend
Occupancy expenses
us-gaap_PaymentsToAcquireIntangibleAssets
Purchase of customer list
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchase of bank premises and equipment
Purchase of bank premises and equipment
Tier one leverage capital to average assets
Net income
Net income
Net income
Tier one leverage capital required to be well capitalized to average assets
Tier one leverage capital required for capital adequacy to risk weighted assets
Capital required to be well capitalized to risk weighted assets
Capital required for capital adequacy to risk weighted assets
Common equity tier one risk based capital to risk weighted assets
Other assets
Tier one risk based capital required to be well capitalized to risk weighted assets
us-gaap_RelatedPartyDepositLiabilities
Related Party Deposit Liabilities
Capital to risk weighted assets
Standby Letters of Credit [Member]
Tier one risk based capital required for capital adequacy to risk weighted assets
Tier one risk based capital to risk weighted assets
Capital
us-gaap_FiniteLivedIntangibleAssetsNet
Intangible asset, net
Intangible asset, net
Capital required to be well capitalized
Capital required for capital adequacy
us-gaap_FinancingReceivableModificationsRecordedInvestment
Financing Receivable, Modifications, Recorded Investment
Tier one leverage capital required to be well capitalized
us-gaap_FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down
Intangible asset, accumulated amortization
Intangible asset, gross amount
Transfer of loans to other real estate owned
Other real real estate owned sale financed by a loan receivable
Common equity tier one capital required to be well capitalized
us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Tier one leverage capital required for capital adequacy
Tier one leverage capital
us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Financing Receivable, Modifications, Subsequent Default, Number of Contracts
Financing receivable modifications, number of contracts
Financing Receivable, Modifications, Number of Contracts
Financing receivable modifications, post modification outstanding, recorded investment
us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Common equity tier one capital required for capital adequacy
Statement of Comprehensive Income [Abstract]
atlo_NetProceedsFromTheSaleOfOtherRealEstate
Net proceeds from sale
The net cash inflow, including non-cash items, associated with the sale of other real estate not otherwise defined in the taxonomy.
Financing receivable modifications, pre-modification outstanding, recorded investment
Common equity tier one capital
Tier one risk based capital
Tier one risk based capital required to be well capitalized
Payment Deferral [Member]
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING ACTIVITIES
Tier one risk based capital required for capital adequacy
Loan Restructuring Modification [Axis]
us-gaap_InterestExpense
Total interest expense
Total interest expense
Loan Restructuring Modification [Domain]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]
Goodwill
Regulatory Capital Requirements under Banking Regulations [Text Block]
Impaired Financing Receivables [Table Text Block]
Bank premises and equipment, net
Troubled Debt Restructurings on Financing Receivables [Table Text Block]
us-gaap_LongTermDebtFairValue
Other borrowings
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Less accumulated depreciation
Other borrowed funds
Property, plant and equipment, gross
Total other borrowings, Weighted average interest rate
us-gaap_TableTextBlock
Notes Tables
Nonperforming Financial Instruments [Member]
Performing Financial Instruments [Member]
Investment in bank subsidiaries
Financing Receivable Credit Quality Indicators [Table Text Block]
Time deposits
us-gaap_InterestExpenseDeposits
Deposits
Financial Instrument Performance Status [Domain]
Financial Instrument Performance Status [Axis]
Savings and money market
Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs), combined with the amount of deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts.
Financing receivable, recorded investment, current
atlo_TierOneRiskBasedCapitalConservationBufferRequiredForCapitalAdequacyToRiskWeightedAssets
Tier One Risk Based Capital Conservation Buffer Required for Capital Adequacy to Risk Weighted Assets
The capital conservation buffer for the required for Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Interest bearing deposits and federal funds sold
Interest income derived from funds deposited with both domestic and foreign financial institutions including funds in money market and other accounts. And, interest income on federal funds sold. Federal funds sold represent the excess federal funds held by one commercial bank which it lends to another commercial bank, usually at an agreed-upon (federal funds) rate of interest. Such loans are made for legal reserve requirement purposes of the borrowing bank and generally are of short-duration (overnight).
atlo_CapitalConservationBufferToRiskWeightedAssets
Capital Conservation Buffer to Risk Weighted Assets
The conservation buffer for the total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Financing receivable, recorded investment, 90 days past due and still accruing
us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Financing Receivable, Recorded Investment, Nonaccrual Status
atlo_CommonEquityTierOneRiskBasedCapitalConservationBufferRequiredForCapitalAdequacyToRiskWeightedAssets
Common Equity Tier One Risk Based Capital Conservation Buffer Required for Capital Adequacy to Risk Weighted Assets
The capital conservation buffer for the common equity tier one capital ratio (tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Other real estate owned (income) expense, net
The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, write-downs of other real estate owned after acquisition or physical possession and expenses and income in connection with holding other real estate owned.
Merchant and card fees
Fee income from merchant card transactions and ATM operations.
Financing receivable, recorded investment, past due
Federal Home Loan Bank (FHLB) advances