Entity tax identification number Entity Tax Identification Number Rollovers EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Maximum Maximum [Member] Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] EBP 001 EBP 001 [Member] EBP 001 Subsequent Event Subsequent Event [Member] Minimum age for withdrawal without penalty EBP, Plan Benefits, Minimum Age For Withdrawal Without Penalty EBP, Plan Benefits, Minimum Age For Withdrawal Without Penalty Sales, amount EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] Pretax, maximum annual compensation to total compensation, percentage EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Maximum borrowing, amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Fair Value Measurements EBP, Investment, Fair Value and NAV [Text Block] Common investment trust funds EBP, Investment Trust Fund [Member] EBP, Investment Trust Fund Total investments EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Subsequent Event Type [Domain] Subsequent Event Type [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] EBP, Investment, Fair Value and NAV [Abstract] Assets: EBP, Asset [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] Additions to Net Assets Available for Benefits Attributed to: EBP, Change in Net Asset Available for Benefit, Increase [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Distributions to Participants EBP, Payment to Participant [Policy Text Block] Amendment Flag Amendment Flag Basis of Presentation EBP, Basis of Accounting [Policy Text Block] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Registered investment companies EBP, Investment Company [Member] EBP, Investment Company Number of shares (in shares) EBP, Investment, Number of Shares EBP, Description of Plan and Accounting Change [Abstract] Receivables: EBP, Receivable [Abstract] EBP, Investment, Fair Value and NAV EBP, Investment, Fair Value and NAV [Table Text Block] Participant compensation matched at 75%, percentage EBP, Employer Contribution, Participant Compensation Matched On Percentage Of Earnings, Percentage EBP, Employer Contribution, Participant Compensation Matched On Percentage Of Earnings, Percentage EBP, Employer, Common Stock And ESOP Stock EBP, Employer, Common Stock And ESOP Stock [Member] EBP, Employer, Common Stock And ESOP Stock Investments [Domain] Investments [Domain] Use of Estimates EBP, Use of Estimate [Policy Text Block] Schedule H, Line 4i – Schedule of Assets (Held At End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Tennant Company (employer) EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash Minimum Minimum [Member] Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Investment Type [Axis] Investment Type [Axis] Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Participants EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Dividends and interest EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment Involuntary cash-out threshold EBP, Involuntary Cash-Out Threshold EBP, Involuntary Cash-Out Threshold EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] Plan Description EBP, Description of Plan [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] Tennant Company common stock EBP, Employer, Common Stock [Member] EBP, Schedule of Asset Held for Investment [Abstract] EBP, Accounting Policy [Table] EBP, Accounting Policy [Table] Total increase EBP, Change in Net Asset Available for Benefit, Increase Investment results: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Total assets held for investment EBP, Asset Held for Investment Risks and Uncertainties EBP, Risk and Uncertainty [Policy Text Block] Document Information [Line Items] Document Information [Line Items] Notes from participants EBP, Notes From Participants [Member] EBP, Notes From Participants Net assets available for benefits: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) [Abstract] Participant compensation matched, maximum amount, percentage EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Basis spread on variable rate EBP, Participant Loan, Basis Spread On Variable Rate EBP, Participant Loan, Basis Spread On Variable Rate Subsequent Event Type [Axis] Subsequent Event Type [Axis] EBP, Tax Status [Table] EBP, Tax Status [Table] Net increase in net assets EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] Discretionary annual contributions EBP, Discretionary Annual Contributions, Amount EBP, Discretionary Annual Contributions, Amount EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Total receivables EBP, Receivable Tennant Company contributions EBP, Employer Contribution, Receivable Automatic deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Investments at fair value: EBP, Investment, Fair Value [Abstract] Distributions to participants EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Dividends — Tennant Company common stock Dividends, amount EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment Current value EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] Administrative Expense EBP, Expense [Policy Text Block] Notes from participants EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Investment Valuation and Income Recognition EBP, Investment [Policy Text Block] True-up matching contributions EBP, True-Up Matching Contributions, Amount EBP, True-Up Matching Contributions, Amount Document Type Document Type Entity Central Index Key Entity Central Index Key Participant loan, interest rate EBP, Asset Held for Investment, Participant Loan, Interest Rate EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Deductions From Net Assets Available for Benefits Attributed to: EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Notes from participants EBP, Note Receivable from Participant Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Purchases, amount EBP, Investment Acquired, Excluding Plan Interest in Master Trust, Cost Investment, cost EBP, Investment, Excluding Plan Interest in Master Trust, Cost Subsequent Events EBP, Subsequent Event [Policy Text Block] Tax Status EBP, Tax Status [Text Block] Maximum borrowing, to total account, percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Par value (in dollars per share) EBP, Investment, Par or Maturity Value Maximum number of allowed notes outstanding EBP, Note Receivable from Participant, Maximum Number Of Notes Outstanding EBP, Note Receivable from Participant, Maximum Number Of Notes Outstanding Document Information [Table] Document Information [Table] Notes Receivable from Participants EBP, Note Receivable from Participant [Policy Text Block] Participant vesting percentage EBP, Employee Vesting Percentage EBP, Employee Vesting Percentage Net investment results EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Level 3 Fair Value, Inputs, Level 3 [Member] Net assets available for benefits Beginning of year End of year EBP, Net Asset Available for Benefit Entity [Domain] Entity [Domain] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Matching percentage EBP, Employer Contribution, Matching Percentage EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items]