v3.22.4
Property, plant and equipment - Right-of-Use Assets Rollforward (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets $ 12,206  
Ending, Right-of-use assets 12,017 $ 12,206
Property    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 11,837  
Ending, Right-of-use assets 11,487 11,837
Equipment    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 139  
Ending, Right-of-use assets 116 139
Vehicle    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 230  
Ending, Right-of-use assets 414 230
Cost    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 26,974 25,022
Additions 3,049 2,013
De-recognition (25)  
Additions through acquisition   174
Transfer (341) (159)
Effect of movements in exchange rates 12 (76)
Ending, Right-of-use assets 29,669 26,974
Cost | Property    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 26,427 24,665
Additions 2,746 1,967
De-recognition 0  
Additions through acquisition   0
Transfer (341) (137)
Effect of movements in exchange rates 12 (68)
Ending, Right-of-use assets 28,844 26,427
Cost | Equipment    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 175 149
Additions 13 46
De-recognition 0  
Additions through acquisition   0
Transfer 0 (22)
Effect of movements in exchange rates 0 2
Ending, Right-of-use assets 188 175
Cost | Vehicle    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets 372 208
Additions 290 0
De-recognition (25)  
Additions through acquisition   174
Transfer 0 0
Effect of movements in exchange rates 0 (10)
Ending, Right-of-use assets 637 372
Accumulated depreciation    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets (14,768) (12,248)
De-recognition (6)  
Transfer (341) (159)
Depreciation 3,231 2,715
Effect of movements in exchange rates 0 (36)
Ending, Right-of-use assets (17,652) (14,768)
Accumulated depreciation | Property    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets (14,590) (12,128)
De-recognition 0  
Transfer (341) (137)
Depreciation 3,108 2,633
Effect of movements in exchange rates 0 (34)
Ending, Right-of-use assets (17,357) (14,590)
Accumulated depreciation | Equipment    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets (36) (28)
De-recognition 0  
Transfer 0 (22)
Depreciation 36 28
Effect of movements in exchange rates 0 2
Ending, Right-of-use assets (72) (36)
Accumulated depreciation | Vehicle    
Right-of-Use Assets [Roll Forward]    
Beginning, Right-of-use assets (142) (92)
De-recognition (6)  
Transfer 0 0
Depreciation 87 54
Effect of movements in exchange rates 0 (4)
Ending, Right-of-use assets $ (223) $ (142)