v3.26.1
Fair Value Measurements (Details) - EBP 001 - USD ($)
Dec. 31, 2025
Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments $ 479,975,810 $ 439,352,493
Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 83,299,572 86,890,829
Tennant Company common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 19,228,344 23,295,226
Common investment trust funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 377,447,894 329,166,438
Level 1    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 102,527,916 110,186,055
Level 1 | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 83,299,572 86,890,829
Level 1 | Tennant Company common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 19,228,344 23,295,226
Level 1 | Common investment trust funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 2    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 377,447,894 329,166,438
Level 2 | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 2 | Tennant Company common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 2 | Common investment trust funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 377,447,894 329,166,438
Level 3    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 3 | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 3 | Tennant Company common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments 0 0
Level 3 | Common investment trust funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments $ 0 $ 0