Employees
| Concept | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2022-10-20 | As at 2022-10-20 | As at 2021-10-20 | As at 2021-10-20 | As at 2020-10-20 | As at 2020-10-20 | As at 2019-10-20 | As at 2019-10-20 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Employees | ||||||||||||||||
| Information about group | ||||||||||||||||
| Number of employees of group | ||||||||||||||||
| Number of employees | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                149
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                156
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                177
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                187
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                188
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                170
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                164
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |