Employees
| Concept | As at 2025-03-31 | 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 | 
                                                1,076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                901
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                877
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,056
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,001
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                827
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                759
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                925
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                916
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                769
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                212
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                212
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                190
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                176
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                192
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                172
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                161
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                169
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                171
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                174
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                172
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |