Employees
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Employees | ||||||||||
| Information about group | ||||||||||
| Number of employees of group | ||||||||||
| Number of employees | 
                                                556
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                491
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                470
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                532
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                535
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                478
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                471
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                523
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                505
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                457
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                124
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                104
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                108
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                106
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                105
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                112
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                108
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |