v3.23.1
Share based compensation - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Nov. 18, 2022
Sep. 01, 2022
Aug. 11, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based payment charge $ 2.1 $ 0.1 $ 0.7      
Share options            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards, expiration period 5 years          
Aggregate number of share options authorized (in shares) 10,897,000          
Fair values of the share options         $ 8.0 $ 2.6
Weighted average remaining life for vested options 8 months 15 days 1 year 2 months 8 days 2 years 3 days      
Share options | Minimum            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period 18 months          
Share options | Maximum            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period 4 years          
Performance stock units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Granted during the year (in shares) 500,000          
Vesting requirement share price (in USD per share) $ 10.00          
Vesting requirement % of days 75.00%          
Share-based payment charge $ 0.1          
Fair value of award         $ 1.0  
Restricted share units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Granted during the year (in shares) 88,584          
Share-based payment charge $ 0.1          
Fair value of award       $ 0.5