Key Financial Data Of Reporting Company
| Concept | 2023-04-01 to 2023-12-31 | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | 
                                                10,094,095,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,310,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,839,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                265,548,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                293,825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                95,410,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                2,487,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,198,461,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,077,398,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                8,336,521,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,598,008,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,693,711,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                47.38
                                                
                                             | — | 
                                                30.22
                                                
                                             | — | 
                                                -38.20
                                                
                                             | — | 
                                                -58.87
                                                
                                             | 
                                                18.73
                                                
                                             | 
| Diluted earnings per share | 
                                                46.24
                                                
                                             | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.298
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.333
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.310
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |