Key Financial Data Of Group
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Revenue | 
                                                4,805,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,143,154,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,810,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                438,346,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                795,796,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                295,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                7,563,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,419,776,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,341,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                13,840,827,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,950,101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,553,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                60.28
                                                
                                             | — | — | 
                                                85.15
                                                
                                             | 
                                                39.57
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.546
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.532
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.542
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                569,509,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,191,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                350,009,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -967,863,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -523,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -209,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -143,209,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -286,137,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -143,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                3,557,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,099,395,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,714,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |