XML 113 R100.htm IDEA: XBRL DOCUMENT v3.22.4
Stock plans - Additional Information (Details) - 2017 Plan - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award        
Common stock available for grant as awards 17,364      
Granted shares 19,787 19,818 16,269  
Vested shares 16,403 15,460 8,455  
Number of nonvested restricted stock awards 39,470 36,281 31,923 25,984
Forfeited shares 195 0 1,875  
Salaries and employee benefits expense $ 0.5 $ 0.5 $ 0.6  
Non-Performance-based restricted stock        
Share-based Compensation Arrangement by Share-based Payment Award        
Granted shares   4,403    
Shares or units awarded 4,396      
Number of nonvested restricted stock awards 3,846 3,128    
Shares or units vesting period 3 years 3 years 3 years  
Performance-based restricted stock units        
Share-based Compensation Arrangement by Share-based Payment Award        
Granted shares 15,390 15,415    
Number of nonvested restricted stock awards 12,557 12,332    
Shares or units vesting period 3 years 3 years 3 years  
Cumulative diluted earnings per share period used for conditions for vesting of performance-based restricted stock units 3 years 3 years 3 years  
Average return on equity period used for conditions for vesting of performance-based restricted stock units 3 years 3 years 3 years  
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award        
Unrecognized compensation expense $ 1.0      
Weighted average vesting period 1 year 8 months 12 days