Key Financial Data Of Group
| Concept | As at 2024-06-30 | 2024-01-01 to 2024-06-30 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-06-30 | 2023-01-01 to 2023-06-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Operating revenue | — | 
                                                652,961,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,369,551,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                684,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                -745,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                120,158,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                50,073,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,414,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,451,788,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,490,978,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                2,693,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,013,606,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,180,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                -1.25
                                                
                                             | 
                                                19.10
                                                
                                             | — | — | 
                                                8.00
                                                
                                             | 
| Diluted earnings per share | — |  | 
                                                18.91
                                                
                                             | — | — | 
                                                7.90
                                                
                                             | 
| Equity-to-asset ratio | 
                                                0.525
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.480
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.466
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -144,261,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                344,370,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                214,532,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -217,368,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -17,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -9,788,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -43,482,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -116,933,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -54,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                1,010,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,416,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,356,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |