Key Financial Data Of Reporting Company
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | — | 
                                                1,535,239,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,016,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,442,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                143,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                330,477,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                140,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                3,574,997,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,457,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,245,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                4,022,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,919,796,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,691,464,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                38.60
                                                
                                             | 
                                                105.33
                                                
                                             | — | — | 
                                                38.48
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.889
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.882
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.879
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                12,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                660,976,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                320,055,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -4,060,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -500,029,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -218,332,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                2,612,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,603,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,544,459,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |