Employees
| Concept | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 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 | 
                                                1,065
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,614
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                347
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                533
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                334
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                185
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                945
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,335
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,505
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,045
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,019
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,419
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,087
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,000
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                959
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,003
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |