Employees
| 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 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 | 
                                                1,392
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,261
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,173
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8,811
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,529
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                27,287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,429
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,864
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13,686
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,597
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28,693
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29,926
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,784
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,989
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                36,900
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                38,471
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,133
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                211
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                257
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                323
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                372
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                308
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,239
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                947
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                413
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,302
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                828
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,229
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,788
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                681
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                597
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,937
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,211
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                501
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |