XML 104 R84.htm IDEA: XBRL DOCUMENT v3.22.4
Stock compensation plans - Summary of non vested restricted stock unit activity (Detail) - Restricted Stock Units - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Number of non-vested shares, outstanding, beginning of the year (in shares) 135,378    
Number of non-vested shares, granted (in shares) 85,780    
Number of non-vested shares, vested (in shares) (51,831)    
Number of non-vested shares, forfeited (in shares) (21,359)    
Number of non-vested shares, outstanding, end of the year (in shares) 147,968 135,378  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]      
Weighted average grant date fair value, outstanding, beginning of the year (in dollars per share) $ 343.89    
Weighted average grant date fair value, granted (in dollars per share) 323.35 $ 398.59 $ 344.70
Weighted average grant date fair value, vested (in dollars per share) 290.75    
Weighted average grant date fair value, forfeited (in dollars per share) 352.06    
Weighted average grant date fair value, outstanding, end of the year (in dollars per share) $ 349.42 $ 343.89  
Weighted average remaining contractual life In years, outstanding, end of the year 1 year 6 months    
Aggregate intrinsic value, outstanding, end of the year $ 36,970