Employees
| Concept | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2020-12-31 | As at 2020-12-31 | As at 2019-12-31 | As at 2019-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Employees | |||||||||||||
| Information about group | |||||||||||||
| Number of employees of group | |||||||||||||
| Number of employees | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                118
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                85
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                138
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                45
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                38
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |