v3.26.1
Stock-Based Compensation Plans - Narrative (Details)
$ in Millions
3 Months Ended 6 Months Ended
Jul. 01, 2022
shares
Jun. 30, 2026
USD ($)
plan
shares
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
plan
shares
Jun. 30, 2025
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense for share-based payments | $   $ 10.0 $ 7.6 $ 20.5 $ 16.3
2019 Omnibus Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share awards made (in shares)       12,853,474  
Shares granted (in shares)       38,498,119  
Shares available to be issued (in shares)   45,000,000   45,000,000  
2026 Omnibus Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share awards made (in shares)       407,858  
Shares granted (in shares)       1,141,562  
Shares available to be issued (in shares)   30,000,000   30,000,000  
Employee Stock Option Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized compensation cost | $   $ 2.8   $ 2.8  
Employee Stock Option Plan | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period       1 year  
Award expiration period       5 years  
Employee Stock Option Plan | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period       5 years  
Award expiration period       10 years  
Second Restricted Stock Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized compensation cost | $   55.4   $ 55.4  
Maximum restricted period       10 years  
Restricted compensation expense | $   $ 6.4 5.0 $ 12.5 10.9
2022 Gentex Corporation Employee Stock Purchase Plan | Employee Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares granted (in shares)       858,195  
Shares available to be issued (in shares) 2,000,000        
ESPP discount rate 85.00%        
ESPP discount rate recognized as compensation expense 15.00%        
Stock Compensation Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of plans | plan   2   2  
Performance Shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense for share-based payments | $   $ 1.9 0.9 $ 4.8 2.0
Unrecognized compensation cost | $   18.4   $ 18.4  
Performance Shares | 2019 Omnibus Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares granted (in shares)       7,090,619  
Performance Share Awards          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense for share-based payments | $   $ 0.5 $ 1.0 $ 0.5 $ 1.0
Award vesting period       4 years