3.10.0.1 html 417 511 1 false 90 0 false 8 false false R1.htm 0001000 - Document - Document and Entity Information Sheet http://westbankiowa.com/role/DocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 1001000 - Statement - Consolidated Balance Sheets Sheet http://westbankiowa.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 2 false false R3.htm 1002500 - Statement - Consolidated Balance Sheets (Parentheticals) Sheet http://westbankiowa.com/role/ConsolidatedBalanceSheetsParentheticals Consolidated Balance Sheets (Parentheticals) Statements 3 false false R4.htm 1003000 - Statement - Consolidated Statements of Income Sheet http://westbankiowa.com/role/ConsolidatedStatementsOfIncome Consolidated Statements of Income Statements 4 false false R5.htm 1004000 - Statement - Consolidated Statements of Comprehensive Income Sheet http://westbankiowa.com/role/ConsolidatedStatementsOfComprehensiveIncome Consolidated Statements of Comprehensive Income Statements 5 false false R6.htm 1005000 - Statement - Consolidated Statements of Stockholders' Equity Sheet http://westbankiowa.com/role/ConsolidatedStatementsOfStockholdersEquity Consolidated Statements of Stockholders' Equity Statements 6 false false R7.htm 1006500 - Statement - Consolidated Statements of Stockholders' Equity (Parentheticals) Sheet http://westbankiowa.com/role/ConsolidatedStatementsOfStockholdersEquityParentheticals Consolidated Statements of Stockholders' Equity (Parentheticals) Statements 7 false false R8.htm 1007000 - Statement - Consolidated Statements of Cash Flows Sheet http://westbankiowa.com/role/ConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows Statements 8 false false R9.htm 2101100 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (Notes) Notes http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesNotes Organization and Nature of Business and Summary of Significant Accounting Policies (Notes) Notes 9 false false R10.htm 2107100 - Disclosure - Earnings per Common Share (Notes) Notes http://westbankiowa.com/role/EarningsPerCommonShareNotes Earnings per Common Share (Notes) Notes 10 false false R11.htm 2110100 - Disclosure - Investment securities (Notes) Notes http://westbankiowa.com/role/InvestmentSecuritiesNotes Investment securities (Notes) Notes 11 false false R12.htm 2113100 - Disclosure - Loans and Allowance for Loan Losses (Notes) Notes http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesNotes Loans and Allowance for Loan Losses (Notes) Notes 12 false false R13.htm 2119100 - Disclosure - Premises and Equipment, Net (Notes) Notes http://westbankiowa.com/role/PremisesAndEquipmentNetNotes Premises and Equipment, Net (Notes) Notes 13 false false R14.htm 2125100 - Disclosure - Deposits (Notes) Notes http://westbankiowa.com/role/DepositsNotes Deposits (Notes) Notes 14 false false R15.htm 2128100 - Disclosure - Subordinated Notes (Notes) Notes http://westbankiowa.com/role/SubordinatedNotesNotes Subordinated Notes (Notes) Notes 15 false false R16.htm 2131100 - Disclosure - Federal Home Loan Bank Advances (Notes) Notes http://westbankiowa.com/role/FederalHomeLoanBankAdvancesNotes Federal Home Loan Bank Advances (Notes) Notes 16 false false R17.htm 2134100 - Disclosure - Long-term debt (Notes) Notes http://westbankiowa.com/role/LongTermDebtNotes Long-term debt (Notes) Notes 17 false false R18.htm 2137100 - Disclosure - Derivatives (Notes) Notes http://westbankiowa.com/role/DerivativesNotes Derivatives (Notes) Notes 18 false false R19.htm 2140100 - Disclosure - Income Taxes (Notes) Notes http://westbankiowa.com/role/IncomeTaxesNotes Income Taxes (Notes) Notes 19 false false R20.htm 2143100 - Disclosure - Stock Compensation Plans (Notes) Notes http://westbankiowa.com/role/StockCompensationPlansNotes Stock Compensation Plans (Notes) Notes 20 false false R21.htm 2146100 - Disclosure - Employee Savings and Stock Ownership Plan (Notes) Notes http://westbankiowa.com/role/EmployeeSavingsAndStockOwnershipPlanNotes Employee Savings and Stock Ownership Plan (Notes) Notes 21 false false R22.htm 2155100 - Disclosure - Accumulated Other Comprehensive Income (Notes) Notes http://westbankiowa.com/role/AccumulatedOtherComprehensiveIncomeNotes Accumulated Other Comprehensive Income (Notes) Notes 22 false false R23.htm 2156100 - Disclosure - Regulatory Capital Requirements (Notes) Notes http://westbankiowa.com/role/RegulatoryCapitalRequirementsNotes Regulatory Capital Requirements (Notes) Notes 23 false false R24.htm 2157100 - Disclosure - Commitments and Contingencies (Notes) Notes http://westbankiowa.com/role/CommitmentsAndContingenciesNotes Commitments and Contingencies (Notes) Notes 24 false false R25.htm 2158100 - Disclosure - Fair Value Measurements (Notes) Notes http://westbankiowa.com/role/FairValueMeasurementsNotes Fair Value Measurements (Notes) Notes 25 false false R26.htm 2159100 - Disclosure - West Bancorporation, Inc. (Parent Company Only) Condensed Financial Statements (Notes) Notes http://westbankiowa.com/role/WestBancorporationIncParentCompanyOnlyCondensedFinancialStatementsNotes West Bancorporation, Inc. (Parent Company Only) Condensed Financial Statements (Notes) Notes 26 false false R27.htm 2160100 - Disclosure - Selected Quarterly Financial Data (unaudited) (Notes) Notes http://westbankiowa.com/role/SelectedQuarterlyFinancialDataUnauditedNotes Selected Quarterly Financial Data (unaudited) (Notes) Notes 27 false false R28.htm 2201201 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (Policies) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies Organization and Nature of Business and Summary of Significant Accounting Policies (Policies) Policies http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesNotes 28 false false R29.htm 2307301 - Disclosure - Earnings per Common Share (Tables) Sheet http://westbankiowa.com/role/EarningsPerCommonShareTables Earnings per Common Share (Tables) Tables http://westbankiowa.com/role/EarningsPerCommonShareNotes 29 false false R30.htm 2310301 - Disclosure - Investment securities (Tables) Sheet http://westbankiowa.com/role/InvestmentSecuritiesTables Investment securities (Tables) Tables http://westbankiowa.com/role/InvestmentSecuritiesNotes 30 false false R31.htm 2313301 - Disclosure - Loans and Allowance for Loan Losses (Tables) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesTables Loans and Allowance for Loan Losses (Tables) Tables http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesNotes 31 false false R32.htm 2319301 - Disclosure - Premises and Equipment, Net (Tables) Sheet http://westbankiowa.com/role/PremisesAndEquipmentNetTables Premises and Equipment, Net (Tables) Tables http://westbankiowa.com/role/PremisesAndEquipmentNetNotes 32 false false R33.htm 2325301 - Disclosure - Deposits (Tables) Sheet http://westbankiowa.com/role/DepositsTables Deposits (Tables) Tables http://westbankiowa.com/role/DepositsNotes 33 false false R34.htm 2331301 - Disclosure - Federal Home Loan Bank Advances (Tables) Sheet http://westbankiowa.com/role/FederalHomeLoanBankAdvancesTables Federal Home Loan Bank Advances (Tables) Tables http://westbankiowa.com/role/FederalHomeLoanBankAdvancesNotes 34 false false R35.htm 2334301 - Disclosure - Long-term debt (Tables) Sheet http://westbankiowa.com/role/LongTermDebtTables Long-term debt (Tables) Tables http://westbankiowa.com/role/LongTermDebtNotes 35 false false R36.htm 2337301 - Disclosure - Derivatives (Tables) Sheet http://westbankiowa.com/role/DerivativesTables Derivatives (Tables) Tables http://westbankiowa.com/role/DerivativesNotes 36 false false R37.htm 2340301 - Disclosure - Income Taxes (Tables) Sheet http://westbankiowa.com/role/IncomeTaxesTables Income Taxes (Tables) Tables http://westbankiowa.com/role/IncomeTaxesNotes 37 false false R38.htm 2343301 - Disclosure - Stock Compensation Plans (Tables) Sheet http://westbankiowa.com/role/StockCompensationPlansTables Stock Compensation Plans (Tables) Tables http://westbankiowa.com/role/StockCompensationPlansNotes 38 false false R39.htm 2355301 - Disclosure - Accumulated Other Comprehensive Income (Tables) Sheet http://westbankiowa.com/role/AccumulatedOtherComprehensiveIncomeTables Accumulated Other Comprehensive Income (Tables) Tables http://westbankiowa.com/role/AccumulatedOtherComprehensiveIncomeNotes 39 false false R40.htm 2356301 - Disclosure - Regulatory Capital Requirements (Tables) Sheet http://westbankiowa.com/role/RegulatoryCapitalRequirementsTables Regulatory Capital Requirements (Tables) Tables http://westbankiowa.com/role/RegulatoryCapitalRequirementsNotes 40 false false R41.htm 2357301 - Disclosure - Commitments and Contingencies (Tables) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesTables Commitments and Contingencies (Tables) Tables http://westbankiowa.com/role/CommitmentsAndContingenciesNotes 41 false false R42.htm 2358301 - Disclosure - Fair Value Measurements (Tables) Sheet http://westbankiowa.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://westbankiowa.com/role/FairValueMeasurementsNotes 42 false false R43.htm 2359301 - Disclosure - West Bancorporation, Inc. (Parent Company Only) Condensed Financial Statements (Tables) Sheet http://westbankiowa.com/role/WestBancorporationIncParentCompanyOnlyCondensedFinancialStatementsTables West Bancorporation, Inc. (Parent Company Only) Condensed Financial Statements (Tables) Tables http://westbankiowa.com/role/WestBancorporationIncParentCompanyOnlyCondensedFinancialStatementsNotes 43 false false R44.htm 2360301 - Disclosure - Selected Quarterly Financial Data (unaudited) (Tables) Sheet http://westbankiowa.com/role/SelectedQuarterlyFinancialDataUnauditedTables Selected Quarterly Financial Data (unaudited) (Tables) Tables http://westbankiowa.com/role/SelectedQuarterlyFinancialDataUnauditedNotes 44 false false R45.htm 2401402 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (Branches) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesBranchesDetails Organization and Nature of Business and Summary of Significant Accounting Policies (Branches) (Details) Details http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies 45 false false R46.htm 2401403 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (FHLB stock) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesFhlbStockDetails Organization and Nature of Business and Summary of Significant Accounting Policies (FHLB stock) (Details) Details http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies 46 false false R47.htm 2401404 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (Useful Lives) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesUsefulLivesDetails Organization and Nature of Business and Summary of Significant Accounting Policies (Useful Lives) (Details) Details http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies 47 false false R48.htm 2401405 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (OREO) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesOreoDetails Organization and Nature of Business and Summary of Significant Accounting Policies (OREO) (Details) Details http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies 48 false false R49.htm 2401406 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies (Trust assets) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesTrustAssetsDetails Organization and Nature of Business and Summary of Significant Accounting Policies (Trust assets) (Details) Details http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies 49 false false R50.htm 2401407 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies Organization and Nature of Business and Summary of Significant Accounting Policies (RSUs) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesOrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesRsusDetails Organization and Nature of Business and Summary of Significant Accounting Policies Organization and Nature of Business and Summary of Significant Accounting Policies (RSUs) (Details) Details 50 false false R51.htm 2401408 - Disclosure - Organization and Nature of Business and Summary of Significant Accounting Policies Organization and Nature of Business and Summary of Significant Accounting Policies (Recent Accounting Pronouncements) (Details) Sheet http://westbankiowa.com/role/OrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesOrganizationAndNatureOfBusinessAndSummaryOfSignificantAccountingPoliciesRecentAccountingPronouncementsDetails Organization and Nature of Business and Summary of Significant Accounting Policies Organization and Nature of Business and Summary of Significant Accounting Policies (Recent Accounting Pronouncements) (Details) Details 51 false false R52.htm 2407402 - Disclosure - Earnings per Common Share (Details) Sheet http://westbankiowa.com/role/EarningsPerCommonShareDetails Earnings per Common Share (Details) Details http://westbankiowa.com/role/EarningsPerCommonShareTables 52 false false R53.htm 2410402 - Disclosure - Investment Securities Available-for-Sale by Security Type (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesAvailableForSaleBySecurityTypeDetails Investment Securities Available-for-Sale by Security Type (Details) Details 53 false false R54.htm 2410403 - Disclosure - Investment Securities Held-to-Maturity by Security Type (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesHeldToMaturityBySecurityTypeDetails Investment Securities Held-to-Maturity by Security Type (Details) Details 54 false false R55.htm 2410404 - Disclosure - Investment Securities Contractual Maturity (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesContractualMaturityDetails Investment Securities Contractual Maturity (Details) Details 55 false false R56.htm 2410405 - Disclosure - Investment Securities Detail of Sale of Securities (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesDetailOfSaleOfSecuritiesDetails Investment Securities Detail of Sale of Securities (Details) Details 56 false false R57.htm 2410406 - Disclosure - Investment Securities Gross Unrealized Losses - AFS (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesGrossUnrealizedLossesAfsDetails Investment Securities Gross Unrealized Losses - AFS (Details) Details 57 false false R58.htm 2410407 - Disclosure - Investment Securities Gross Unrealized Losses - HTM (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesGrossUnrealizedLossesHtmDetails Investment Securities Gross Unrealized Losses - HTM (Details) Details 58 false false R59.htm 2410408 - Disclosure - Investment Securities Other Narratives (Details) Sheet http://westbankiowa.com/role/InvestmentSecuritiesOtherNarrativesDetails Investment Securities Other Narratives (Details) Details 59 false false R60.htm 2413402 - Disclosure - Loans and Allowance for Loan Losses Schedule of Loans (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfLoansDetails Loans and Allowance for Loan Losses Schedule of Loans (Details) Details 60 false false R61.htm 2413403 - Disclosure - Loans and Allowance for Loan Losses Schedule of Loan Transactions with Related Parties (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfLoanTransactionsWithRelatedPartiesDetails Loans and Allowance for Loan Losses Schedule of Loan Transactions with Related Parties (Details) Details 61 false false R62.htm 2413404 - Disclosure - Loans and Allowance for Loan Losses Schedule of Impaired Loans With and Without an Allowance (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfImpairedLoansWithAndWithoutAllowanceDetails Loans and Allowance for Loan Losses Schedule of Impaired Loans With and Without an Allowance (Details) Details 62 false false R63.htm 2413405 - Disclosure - Loans and Allowance for Loan Losses Impaired Loans (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesImpairedLoansDetails Loans and Allowance for Loan Losses Impaired Loans (Details) Details 63 false false R64.htm 2413406 - Disclosure - Loans and Allowance for Loan Losses Schedule of Past Due Loans (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfPastDueLoansDetails Loans and Allowance for Loan Losses Schedule of Past Due Loans (Details) Details 64 false false R65.htm 2413407 - Disclosure - Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loans (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfTroubledDebtRestructuredLoansDetails Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loans (Details) Details 65 false false R66.htm 2413408 - Disclosure - Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loan Modifications (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfTroubledDebtRestructuredLoanModificationsDetails Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loan Modifications (Details) Details 66 false false R67.htm 2413409 - Disclosure - Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loans that Subsequently Defaulted (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfTroubledDebtRestructuredLoansThatSubsequentlyDefaultedDetails Loans and Allowance for Loan Losses Schedule of Troubled Debt Restructured Loans that Subsequently Defaulted (Details) Details 67 false false R68.htm 2413410 - Disclosure - Loans and Allowance for Loan Losses Schedule of Loans by Credit Quality Indicator (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfLoansByCreditQualityIndicatorDetails Loans and Allowance for Loan Losses Schedule of Loans by Credit Quality Indicator (Details) Details 68 false false R69.htm 2413411 - Disclosure - Loans and Allowance for Loan Losses Schedule of Allowance for Loan Loss Activity (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfAllowanceForLoanLossActivityDetails Loans and Allowance for Loan Losses Schedule of Allowance for Loan Loss Activity (Details) Details 69 false false R70.htm 2413412 - Disclosure - Loans and Allowance for Loan Losses Schedule of Allowance for Loan Losses Based on Impairment Method (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfAllowanceForLoanLossesBasedOnImpairmentMethodDetails Loans and Allowance for Loan Losses Schedule of Allowance for Loan Losses Based on Impairment Method (Details) Details 70 false false R71.htm 2413413 - Disclosure - Loans and Allowance for Loan Losses Schedule of Loans by Impairment Method (Details) Sheet http://westbankiowa.com/role/LoansAndAllowanceForLoanLossesScheduleOfLoansByImpairmentMethodDetails Loans and Allowance for Loan Losses Schedule of Loans by Impairment Method (Details) Details 71 false false R72.htm 2419402 - Disclosure - Premises and Equipment, Net (Details) Sheet http://westbankiowa.com/role/PremisesAndEquipmentNetDetails Premises and Equipment, Net (Details) Details http://westbankiowa.com/role/PremisesAndEquipmentNetTables 72 false false R73.htm 2425402 - Disclosure - Deposits Deposits (Details) Sheet http://westbankiowa.com/role/DepositsDepositsDetails Deposits Deposits (Details) Details 73 false false R74.htm 2428401 - Disclosure - Subordinated Notes (Details) Notes http://westbankiowa.com/role/SubordinatedNotesDetails Subordinated Notes (Details) Details http://westbankiowa.com/role/SubordinatedNotesNotes 74 false false R75.htm 2431402 - Disclosure - Federal Home Loan Bank Advances, Maturities Summary (Details) Sheet http://westbankiowa.com/role/FederalHomeLoanBankAdvancesMaturitiesSummaryDetails Federal Home Loan Bank Advances, Maturities Summary (Details) Details 75 false false R76.htm 2431403 - Disclosure - Federal Home Loan Bank Advances (Other Narratives) (Details) Sheet http://westbankiowa.com/role/FederalHomeLoanBankAdvancesOtherNarrativesDetails Federal Home Loan Bank Advances (Other Narratives) (Details) Details http://westbankiowa.com/role/FederalHomeLoanBankAdvancesTables 76 false false R77.htm 2434402 - Disclosure - Long-term debt (Details) Sheet http://westbankiowa.com/role/LongTermDebtDetails Long-term debt (Details) Details http://westbankiowa.com/role/LongTermDebtTables 77 false false R78.htm 2434403 - Disclosure - Long-term debt Maturities of long-term debt (Details) Sheet http://westbankiowa.com/role/LongTermDebtMaturitiesOfLongTermDebtDetails Long-term debt Maturities of long-term debt (Details) Details 78 false false R79.htm 2437402 - Disclosure - Derivatives (Details) Sheet http://westbankiowa.com/role/DerivativesDetails Derivatives (Details) Details http://westbankiowa.com/role/DerivativesTables 79 false false R80.htm 2437403 - Disclosure - Derivatives Pre-Tax Losses (Details) Sheet http://westbankiowa.com/role/DerivativesPreTaxLossesDetails Derivatives Pre-Tax Losses (Details) Details 80 false false R81.htm 2440402 - Disclosure - Income Taxes Schedule of Components of Income Tax Expense (Details) Sheet http://westbankiowa.com/role/IncomeTaxesScheduleOfComponentsOfIncomeTaxExpenseDetails Income Taxes Schedule of Components of Income Tax Expense (Details) Details 81 false false R82.htm 2440403 - Disclosure - Income Taxes Schedule of Effective Income Tax Rate Reconciliation (Details) Sheet http://westbankiowa.com/role/IncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationDetails Income Taxes Schedule of Effective Income Tax Rate Reconciliation (Details) Details 82 false false R83.htm 2440404 - Disclosure - Income Taxes Schedule of Deferred Tax Assets and Liabilities (Details) Sheet http://westbankiowa.com/role/IncomeTaxesScheduleOfDeferredTaxAssetsAndLiabilitiesDetails Income Taxes Schedule of Deferred Tax Assets and Liabilities (Details) Details 83 false false R84.htm 2440405 - Disclosure - Income Taxes Schedule of Operating Loss Carryforwards (Details) Sheet http://westbankiowa.com/role/IncomeTaxesScheduleOfOperatingLossCarryforwardsDetails Income Taxes Schedule of Operating Loss Carryforwards (Details) Details 84 false false R85.htm 2440406 - Disclosure - Income Taxes Schedule of Penalties and Interest (Details) Sheet http://westbankiowa.com/role/IncomeTaxesScheduleOfPenaltiesAndInterestDetails Income Taxes Schedule of Penalties and Interest (Details) Details 85 false false R86.htm 2443402 - Disclosure - Stock Compensation Plans Restricted Stock Unit Activity (Details) Sheet http://westbankiowa.com/role/StockCompensationPlansRestrictedStockUnitActivityDetails Stock Compensation Plans Restricted Stock Unit Activity (Details) Details 86 false false R87.htm 2443403 - Disclosure - Stock Compensation Plans Narratives (Details) Sheet http://westbankiowa.com/role/StockCompensationPlansNarrativesDetails Stock Compensation Plans Narratives (Details) Details 87 false false R88.htm 2446401 - Disclosure - Employee Savings and Stock Ownership Plan (Details) Sheet http://westbankiowa.com/role/EmployeeSavingsAndStockOwnershipPlanDetails Employee Savings and Stock Ownership Plan (Details) Details http://westbankiowa.com/role/EmployeeSavingsAndStockOwnershipPlanNotes 88 false false R89.htm 2455402 - Disclosure - Changes in Accumulated Other Comprehensive Income (Details) Sheet http://westbankiowa.com/role/ChangesInAccumulatedOtherComprehensiveIncomeDetails Changes in Accumulated Other Comprehensive Income (Details) Details 89 false false R90.htm 2456402 - Disclosure - Regulatory Capital Requirements (Details) Sheet http://westbankiowa.com/role/RegulatoryCapitalRequirementsDetails Regulatory Capital Requirements (Details) Details http://westbankiowa.com/role/RegulatoryCapitalRequirementsTables 90 false false R91.htm 2457402 - Disclosure - Commitments and Contingencies Rent Expense (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesRentExpenseDetails Commitments and Contingencies Rent Expense (Details) Details 91 false false R92.htm 2457403 - Disclosure - Commitments and Contingencies Minimum Rental Commitments (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesMinimumRentalCommitmentsDetails Commitments and Contingencies Minimum Rental Commitments (Details) Details 92 false false R93.htm 2457404 - Disclosure - Commitments and Contingencies Required Reserve Balances (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesRequiredReserveBalancesDetails Commitments and Contingencies Required Reserve Balances (Details) Details 93 false false R94.htm 2457405 - Disclosure - Commitments and Contingencies Commitments (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesCommitmentsDetails Commitments and Contingencies Commitments (Details) Details 94 false false R95.htm 2457406 - Disclosure - Commitments and Contingencies Other Narratives (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesOtherNarrativesDetails Commitments and Contingencies Other Narratives (Details) Details 95 false false R96.htm 2457407 - Disclosure - Commitments and Contingencies Contractual commitments (Details) Sheet http://westbankiowa.com/role/CommitmentsAndContingenciesContractualCommitmentsDetails Commitments and Contingencies Contractual commitments (Details) Details 96 false false R97.htm 2458402 - Disclosure - Fair Value Measurements Recurring Basis by Level (Details) Sheet http://westbankiowa.com/role/FairValueMeasurementsRecurringBasisByLevelDetails Fair Value Measurements Recurring Basis by Level (Details) Details 97 false false R98.htm 2458403 - Disclosure - Fair Value Measurements Nonrecurring Basis by Level (Details) Sheet http://westbankiowa.com/role/FairValueMeasurementsNonrecurringBasisByLevelDetails Fair Value Measurements Nonrecurring Basis by Level (Details) Details 98 false false R99.htm 2458404 - Disclosure - Fair Value Measurements Carrying Amounts and Fair Values (Details) Sheet http://westbankiowa.com/role/FairValueMeasurementsCarryingAmountsAndFairValuesDetails Fair Value Measurements Carrying Amounts and Fair Values (Details) Details 99 false false R100.htm 2458405 - Disclosure - Fair Value Measurements Narratives (Details) Sheet http://westbankiowa.com/role/FairValueMeasurementsNarrativesDetails Fair Value Measurements Narratives (Details) Details 100 false false R101.htm 2459402 - Disclosure - Condensed Balance Sheets - Parent Company Only (Details) Sheet http://westbankiowa.com/role/CondensedBalanceSheetsParentCompanyOnlyDetails Condensed Balance Sheets - Parent Company Only (Details) Details 101 false false R102.htm 2459403 - Disclosure - Condensed Statements of Income- Parent Company Only (Details) Sheet http://westbankiowa.com/role/CondensedStatementsOfIncomeParentCompanyOnlyDetails Condensed Statements of Income- Parent Company Only (Details) Details 102 false false R103.htm 2459404 - Disclosure - Condensed Statements of Cash Flows - Parent Company Only (Details) Sheet http://westbankiowa.com/role/CondensedStatementsOfCashFlowsParentCompanyOnlyDetails Condensed Statements of Cash Flows - Parent Company Only (Details) Details 103 false false R104.htm 2460402 - Disclosure - Selected Quarterly Financial Data (unaudited) (Details) Sheet http://westbankiowa.com/role/SelectedQuarterlyFinancialDataUnauditedDetails Selected Quarterly Financial Data (unaudited) (Details) Details http://westbankiowa.com/role/SelectedQuarterlyFinancialDataUnauditedTables 104 false false All Reports Book All Reports wtba-20181231.xml wtba-20181231.xsd wtba-20181231_cal.xml wtba-20181231_def.xml wtba-20181231_lab.xml wtba-20181231_pre.xml http://fasb.org/us-gaap/2018-01-31 http://xbrl.sec.gov/dei/2018-01-31 http://xbrl.sec.gov/invest/2013-01-31 http://fasb.org/srt/2018-01-31 true true