XML 99 R78.htm IDEA: XBRL DOCUMENT v3.22.0.1
Stock compensation plans - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Maximum number of common stock authorized to be issued under plan (in shares) 5,300,000    
Number of options granted (in shares) 108,686    
Unrecognized compensation expense $ 37.8    
Shares available for future grants (in shares) 3,082,554    
Stock option granted, weighted average grant date fair value (in dollars per share) $ 103.87 $ 74.60 $ 68.22
Stock option granted, weighted average grant date fair value $ 27.4 $ 77.9 $ 64.3
Stock option expenses including selling general and administrative expenses $ 8.8    
Non-vested restricted stock units issued (in shares) 59,210 52,464 69,799
Non vested restricted stock expense including selling general and administrative expense $ 13.5    
Common Stock      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Number of options granted (in shares) 108,686    
Restricted Stock Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of restricted stock awards (in shares) 59,210    
Stock Option      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation expense $ 9.4    
Period for recognition 1 year 5 months 19 days    
Restricted Stock      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation expense $ 17.7    
Period for recognition 1 year 2 months 12 days    
Restricted Stock Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of restricted stock awards (in shares) 59,210    
Weighted average grant date fair value (in dollars per share) $ 398.59 $ 344.70 $ 286.51
Performance Shares Units (PSUs)      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Performance period 3 years    
Weighted average grant date fair value (in dollars per share)   $ 419.25  
Minimum | Performance Shares Units (PSUs)      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of restricted stock awards (in shares) 16,903    
Maximum | Performance Shares Units (PSUs)      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of restricted stock awards (in shares) 42,272