XML 59 R47.htm IDEA: XBRL DOCUMENT v3.21.2
Share-based payments (Details) - USD ($)
$ / shares in Units, $ in Millions
9 Months Ended
Sep. 30, 2021
Sep. 30, 2019
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Fair value of options granted in the period $ 1.3 $ 3.4  
Number of options granted in the period (in shares) 141,000 648,000  
Average grant price (in usd per share) $ 9.24 $ 5.32  
Strike price (USD per share) $ 53.24   $ 39.76
Time-based shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 3 years    
Performance-based shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award service period 3 years    
Stock options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expiration period 10 years    
Stock options | Tranche one      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting percentage 20.00%    
Stock options | Tranche two      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting percentage 30.00%    
Stock options | Tranche three      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting percentage 50.00%    
Restricted stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Aggregate fair value at grant date $ 9.2 $ 3.8  
Share-based incentives, shares issued 170,000 96,000  
Average grant price (in usd per share) $ 53.70 $ 39.36