Employees
| Concept | As at 2024-07-31 | As at 2023-09-30 | As at 2022-09-30 | As at 2021-09-30 | As at 2020-09-30 | As at 2019-09-30 | 
|---|---|---|---|---|---|---|
| Employees | ||||||
| Information about reporting company | ||||||
| Information about employees of reporting company | ||||||
| Number of employees | 
                                                291
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                212
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                131
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                112
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                72
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                50
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average age (Years) | 
                                                31.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
| Average length of service (Years) | 
                                                1.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
| Average annual salary | 
                                                6,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — |