Key Financial Data Of Reporting Company
| Concept | 2024-01-01 to 2024-03-31 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2023-01-01 to 2023-03-31 | As at 2023-03-31 | 2022-10-01 to 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | — | — | 
                                                4,308,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,257,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,039,712,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | 
                                                375,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                181,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                264,983,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | — | 
                                                1,913,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,584,792,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,628,357,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                4,693,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,582,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,470,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | 
                                                15.00
                                                
                                             | — | 
                                                35.54
                                                
                                             | — | 
                                                12.24
                                                
                                             | 
                                                10.67
                                                
                                             | — | 
                                                23.66
                                                
                                             | 
| Diluted earnings per share | — | — | 
                                                35.50
                                                
                                             | — | 
                                                12.22
                                                
                                             | — | — | 
                                                23.63
                                                
                                             | 
| Equity-to-asset ratio | — | 
                                                0.396
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.334
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.351
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                300,679,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                172,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -88,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -182,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -43,818,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -191,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -192,511,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -153,972,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | 
                                                1,442,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,416,299,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,728,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |