v3.26.1
Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details) - EBP 001
12 Months Ended
Dec. 31, 2025
USD ($)
shares
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity tax identification number 41-0572550
Plan number 001
Total assets held for investment $ 486,122,882
Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 5.25%
Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 10.50%
Registered investment companies  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 83,299,572
Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 377,447,894
Tennant Company common stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of shares (in shares) | shares 260,790
Par value (in dollars per share) $ 0.375
Investment, cost 10,348,156
Current value 19,228,344
Notes from participants  
EBP, Schedule of Asset Held for Investment [Line Items]  
Notes from participants $ 6,147,072
Notes from participants | Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 5.25%
Notes from participants | Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 10.50%
Investment, Identifier [Axis]: Causeway International Value Fund | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 11,417,923
Investment, Identifier [Axis]: DFA Emerging Markets Core Equity Port | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 10,306,455
Investment, Identifier [Axis]: Fidelity U.S. Bond Index Fund | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 7,440,455
Investment, Identifier [Axis]: GMO Benchmark FR ALLOC SER FD R6 | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 688,703
Investment, Identifier [Axis]: L&G MSCI EAFE DC CIT | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 18,293,818
Investment, Identifier [Axis]: L&G Russell 2000 DC CIT | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 21,709,012
Investment, Identifier [Axis]: L&G S&P 500 DC CIT | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 146,990,528
Investment, Identifier [Axis]: MFS International Growth Fund Class R6 MGRDX | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 1,928,057
Investment, Identifier [Axis]: Prudential Core Plus Bond Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 24,986,111
Investment, Identifier [Axis]: Vanguard Fed Money Market | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 21,806,941
Investment, Identifier [Axis]: Vanguard Target 2020 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 3,874,031
Investment, Identifier [Axis]: Vanguard Target 2025 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 11,794,537
Investment, Identifier [Axis]: Vanguard Target 2030 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 28,075,915
Investment, Identifier [Axis]: Vanguard Target 2035 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 25,668,583
Investment, Identifier [Axis]: Vanguard Target 2040 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 20,328,244
Investment, Identifier [Axis]: Vanguard Target 2045 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 24,227,154
Investment, Identifier [Axis]: Vanguard Target 2050 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 22,931,019
Investment, Identifier [Axis]: Vanguard Target 2055 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 15,947,875
Investment, Identifier [Axis]: Vanguard Target 2060 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 8,710,111
Investment, Identifier [Axis]: Vanguard Target 2065 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 2,819,228
Investment, Identifier [Axis]: Vanguard Target 2070 Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 295,859
Investment, Identifier [Axis]: Vanguard Target Income Fund | Common investment trust funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 795,869
Investment, Identifier [Axis]: Vanguard Wellington Fund | Mutual fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 29,711,038