3.26.1 html 81 67 1 false 14 0 false 6 false false R1.htm 0000001 - Document - Cover Sheet http://www.fastenal.com/role/Cover Cover Cover 1 false false R2.htm 0000002 - Statement - Statements of Net Assets Available for Benefits Sheet http://www.fastenal.com/role/StatementsofNetAssetsAvailableforBenefits Statements of Net Assets Available for Benefits Statements 2 false false R3.htm 0000003 - Statement - Statement of Changes in Net Assets Available for Benefits Sheet http://www.fastenal.com/role/StatementofChangesinNetAssetsAvailableforBenefits Statement of Changes in Net Assets Available for Benefits Statements 3 false false R4.htm 0000004 - Disclosure - Plan Description Sheet http://www.fastenal.com/role/PlanDescription Plan Description Notes 4 false false R5.htm 0000005 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.fastenal.com/role/SummaryofSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 5 false false R6.htm 0000006 - Disclosure - Fair Value Measurements Sheet http://www.fastenal.com/role/FairValueMeasurements Fair Value Measurements Notes 6 false false R7.htm 0000007 - Disclosure - Reconciliation of Financial Statements to Form 5500 Sheet http://www.fastenal.com/role/ReconciliationofFinancialStatementstoForm5500 Reconciliation of Financial Statements to Form 5500 Notes 7 false false R8.htm 0000008 - Disclosure - Tax Status Sheet http://www.fastenal.com/role/TaxStatus Tax Status Notes 8 false false R9.htm 0000009 - Disclosure - Exempt Party-in-Interest Transactions Sheet http://www.fastenal.com/role/ExemptPartyinInterestTransactions Exempt Party-in-Interest Transactions Notes 9 false false R10.htm 0000010 - Disclosure - Subsequent Events Sheet http://www.fastenal.com/role/SubsequentEvents Subsequent Events Notes 10 false false R11.htm 0000011 - Disclosure - Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) Sheet http://www.fastenal.com/role/Form5500ScheduleHPartIVLine4iScheduleofAssetsHeldAtEndofYear Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) Notes 11 false false R12.htm 0000012 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://www.fastenal.com/role/SummaryofSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://www.fastenal.com/role/SummaryofSignificantAccountingPolicies 12 false false R13.htm 0000013 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.fastenal.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.fastenal.com/role/FairValueMeasurements 13 false false R14.htm 0000014 - Disclosure - Reconciliation of Financial Statements to Form 5500 (Tables) Sheet http://www.fastenal.com/role/ReconciliationofFinancialStatementstoForm5500Tables Reconciliation of Financial Statements to Form 5500 (Tables) Tables http://www.fastenal.com/role/ReconciliationofFinancialStatementstoForm5500 14 false false R15.htm 0000015 - Disclosure - Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) (Tables) Sheet http://www.fastenal.com/role/Form5500ScheduleHPartIVLine4iScheduleofAssetsHeldAtEndofYearTables Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) (Tables) Tables http://www.fastenal.com/role/Form5500ScheduleHPartIVLine4iScheduleofAssetsHeldAtEndofYear 15 false false R16.htm 0000016 - Disclosure - Plan Description (Details) Sheet http://www.fastenal.com/role/PlanDescriptionDetails Plan Description (Details) Details http://www.fastenal.com/role/PlanDescription 16 false false R17.htm 0000017 - Disclosure - Summary of Significant Accounting Policies (Details) Sheet http://www.fastenal.com/role/SummaryofSignificantAccountingPoliciesDetails Summary of Significant Accounting Policies (Details) Details http://www.fastenal.com/role/SummaryofSignificantAccountingPoliciesPolicies 17 false false R18.htm 0000018 - Disclosure - Fair Value Measurements (Details) Sheet http://www.fastenal.com/role/FairValueMeasurementsDetails Fair Value Measurements (Details) Details http://www.fastenal.com/role/FairValueMeasurementsTables 18 false false R19.htm 0000019 - Disclosure - Reconciliation of Financial Statements to Form 5500 (Details) Sheet http://www.fastenal.com/role/ReconciliationofFinancialStatementstoForm5500Details Reconciliation of Financial Statements to Form 5500 (Details) Details http://www.fastenal.com/role/ReconciliationofFinancialStatementstoForm5500Tables 19 false false R20.htm 0000020 - Disclosure - Exempt Party-in-Interest Transactions (Details) Sheet http://www.fastenal.com/role/ExemptPartyinInterestTransactionsDetails Exempt Party-in-Interest Transactions (Details) Details http://www.fastenal.com/role/ExemptPartyinInterestTransactions 20 false false R21.htm 0000021 - Disclosure - Subsequent Events (Details) Sheet http://www.fastenal.com/role/SubsequentEventsDetails Subsequent Events (Details) Details http://www.fastenal.com/role/SubsequentEvents 21 false false R22.htm 0000022 - Disclosure - Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) (Details) Sheet http://www.fastenal.com/role/Form5500ScheduleHPartIVLine4iScheduleofAssetsHeldAtEndofYearDetails Form 5500, Schedule H, Part IV, Line 4i – Schedule of Assets (Held At End of Year) (Details) Details http://www.fastenal.com/role/Form5500ScheduleHPartIVLine4iScheduleofAssetsHeldAtEndofYearTables 22 false false All Reports Book All Reports fast-20260604.htm fast-20260604.xsd fast-20260604_cal.xml fast-20260604_def.xml fast-20260604_lab.xml fast-20260604_pre.xml http://fasb.org/us-gaap-ebp/2026 http://xbrl.sec.gov/dei/2026 true true