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 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 | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,956
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                68
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,241
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                68
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                61
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,037
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,815
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                57
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,621
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,589
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,630
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,464
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,979
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                26
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8,009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,252
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,565
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,909
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,458
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,832
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,001
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |