3.26.1 html 72 62 1 false 18 0 false 3 false false R1.htm 0000001 - Document - Cover Sheet http://westbankiowa.com/role/Cover Cover Cover 1 false false R2.htm 0000002 - Document - Cover Sheet http://westbankiowa.com/role/Cover_1 Cover Cover 2 false false R3.htm 0000003 - Statement - Employee Benefit Plan, Statement of Net Asset Available for Benefit (Statement) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanStatementofNetAssetAvailableforBenefitStatement Employee Benefit Plan, Statement of Net Asset Available for Benefit (Statement) Statements 3 false false R4.htm 0000004 - Statement - Employee Benefit Plan, Statement of Change in Net Asset Available for Benefit (Statement) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanStatementofChangeinNetAssetAvailableforBenefitStatement Employee Benefit Plan, Statement of Change in Net Asset Available for Benefit (Statement) Statements 4 false false R5.htm 0000014 - Disclosure - Employee Benefit Plan, Summary of Accounting Policy (Tables) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanSummaryofAccountingPolicyTables Employee Benefit Plan, Summary of Accounting Policy (Tables) Tables 5 false false R6.htm 0000020 - Disclosure - Employee Benefit Plan, Description of Plan (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanDescriptionofPlanDetails Employee Benefit Plan, Description of Plan (Details) Details 6 false false R7.htm 0000021 - Disclosure - Employee Benefit Plan, Summary of Accounting Policy (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanSummaryofAccountingPolicyDetails Employee Benefit Plan, Summary of Accounting Policy (Details) Details http://westbankiowa.com/role/EmployeeBenefitPlanSummaryofAccountingPolicyTables 7 false false R8.htm 0000022 - Disclosure - Employee Benefit Plan, Fair Value and NAV (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanFairValueandNAVDetails Employee Benefit Plan, Fair Value and NAV (Details) Details 8 false false R9.htm 0000023 - Disclosure - Employee Benefit Plan, Tax Status (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanTaxStatusDetails Employee Benefit Plan, Tax Status (Details) Details 9 false false R10.htm 0000024 - Disclosure - Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactionsDetails Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Details) Details 10 false false R11.htm 0000025 - Disclosure - Employee Benefit Plan, Comprehensive Text Block (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanComprehensiveTextBlockDetails Employee Benefit Plan, Comprehensive Text Block (Details) Details 11 false false R12.htm 0000026 - Disclosure - Employee Benefit Plan, Schedule, Asset Held for Investment (Details) Sheet http://westbankiowa.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestmentDetails Employee Benefit Plan, Schedule, Asset Held for Investment (Details) Details 12 false false R9999.htm Uncategorized Items - wtba-20251231.htm Sheet http://xbrl.sec.gov/role/uncategorizedFacts Uncategorized Items - wtba-20251231.htm Cover 13 false false All Reports Book All Reports wtba-20251231.htm wtba-20251231.xsd wtba-20251231_def.xml wtba-20251231_lab.xml wtba-20251231_pre.xml http://fasb.org/us-gaap-ebp/2026 http://xbrl.sec.gov/dei/2026 true false