| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 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 | 
                                                799
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                239
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,355
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,594
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,166
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                242
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                400
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,405
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                125
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                239
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                652
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,303
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,634
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,437
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,666
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,750
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,443
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,809
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,483
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                81
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                223
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                266
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                111
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                150
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                40
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                174
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                158
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                153
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                273
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |