Employees
| Concept | As at 2025-03-31 | As at 2024-03-31 | As at 2023-03-31 | As at 2022-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|
| Employees | |||||
| Information about group | |||||
| Number of employees of group | |||||
| Number of employees | 
                                                527
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                597
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                719
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                875
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,020
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                151
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                180
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                183
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |