Employees
| Concept | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | 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 | As at 2019-03-31 | As at 2019-03-31 | As at 2018-03-31 | As at 2018-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Employees | ||||||||||||||||
| Information about reporting company | ||||||||||||||||
| Number of employees of reporting company | ||||||||||||||||
| Number of employees | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                222
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                281
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                288
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                229
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                233
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                291
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                229
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                226
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                23
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |