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 | 
                                                10,359,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,842,071,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,463,017,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                1,180,694,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,244,139,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                952,370,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                7,116,648,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,676,357,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,403,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                9,418,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,338,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,634,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                83.66
                                                
                                             | — | 
                                                31.95
                                                
                                             | — | 
                                                90.41
                                                
                                             | — | 
                                                68.19
                                                
                                             | 
                                                28.33
                                                
                                             | 
| Diluted earnings per share | 
                                                82.58
                                                
                                             | — | — | — | 
                                                89.33
                                                
                                             | — | 
                                                67.37
                                                
                                             | — | 
| Equity-to-asset ratio | — | 
                                                0.740
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.702
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.728
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |