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 reporting company | ||||||||||||||||
| Number of employees of reporting company | ||||||||||||||||
| Number of employees | 
                                                1,312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,363
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,043
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,094
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,055
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,337
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,303
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,017
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                990
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,270
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,198
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                916
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                532
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                546
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                437
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                511
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                479
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                422
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                360
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                419
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                342
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                291
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |