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 | 
                                                5,180,009,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,579,127,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,923,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                437,934,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                431,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                319,352,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                2,377,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,068,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,919,496,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                8,187,255,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,273,419,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,343,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                251.00
                                                
                                             | — | 
                                                102.63
                                                
                                             | — | 
                                                298.08
                                                
                                             | — | 
                                                173.40
                                                
                                             | 
                                                69.80
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.282
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.260
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |