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 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 | ||||||||||||||||||||||
| Information about employees of reporting company | ||||||||||||||||||||||
| Number of employees | 
                                                241
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9,670
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                33,338
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,299
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                105,067
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                47,875
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,725
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                567
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                591
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,828
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                254
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,289
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,241
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,631
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101,453
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,037
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,902
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                102,908
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                116,808
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,719
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                129,284
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,689
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average age (Years) | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                43.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Average length of service (Years) | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                17.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Average annual salary | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                8,302,532
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — |