Employees
| Concept | As at 2024-03-31 | As at 2024-03-31 | 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 | As at 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Employees | ||||||||||||
| Information about group | ||||||||||||
| Number of employees of group | ||||||||||||
| Number of employees | 
                                                661
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                784
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                123
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                661
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                798
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                674
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                675
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                790
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                819
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                706
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                703
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                816
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                5,392
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,970
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                578
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,392
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,612
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,031
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,339
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,938
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,874
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,996
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,608
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |