v3.26.1
Deferred compensation (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Deferred compensation          
Description of deferred compensation arrangements     The Mayville Engineering Company Deferred Compensation Plan is available for certain employees designated to be eligible to participate by the Company and approved by the Board of Directors.    
Deferred compensation arrangements, awards granted percentage     50.00%    
Annual short term cash incentive percentage     100.00%    
Deferred compensation cash-based arrangements liability, Current $ 420   $ 420   $ 1,000
Deferred compensation cash-based arrangements liability, Non current 5,407   5,407   $ 5,240
Deferred compensation plan expense (credit) 4,845 $ 1,525 9,650 $ 4,850  
Deferred compensation, distributions paid     1,000 253  
Deferred Profit Sharing          
Deferred compensation          
Deferred compensation plan expense (credit) 587 383 434 310  
Employees          
Deferred compensation          
Amount of compensation deferred $ 22 $ 75 $ 153 $ 675