Key Financial Data Of Reporting Company
| Concept | 
                                    
                                        As at 2024-05-31  | 
                            
                                
                                    
                                        2024-03-01 to 2024-05-31  | 
                            
                                
                                    
                                        2023-09-01 to 2024-05-31  | 
                            
                                
                                    
                                        As at 2023-08-31  | 
                            
                                
                                    
                                        2022-09-01 to 2023-08-31  | 
                            
                                
                                    
                                        2022-09-01 to 2023-05-31  | 
                            
                                
                                    
                                        2023-03-01 to 2023-05-31  | 
                            
                                
                                    
                                        As at 2023-05-31  | 
                            
                        
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | — | — | 
                                        
                                             
                                                2,302,847,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                2,926,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2,239,861,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Ordinary profit (loss) | — | — | 
                                        
                                             
                                                53,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -47,664,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                -43,456,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Profit (loss) | — | — | 
                                        
                                             
                                                26,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -51,328,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                -57,698,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | — | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Share capital | 
                                        
                                             
                                                287,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                287,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                281,855,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Total number of issued shares | 
                                        
                                             
                                                2,159,286
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                2,159,286
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                2,127,419
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Net assets | 
                                        
                                             
                                                180,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                154,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                136,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Total assets | 
                                        
                                             
                                                1,189,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,109,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                1,144,174,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Dividend paid per share | — | — | 
                                        
                                             | 
                                
                                    — | 
                                        
                                             | 
                                
                                    
                                        
                                             | 
                                
                                    — | — | 
| Basic earnings (loss) per share | — | 
                                        
                                             
                                                2.93
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                12.36
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -24.41
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                -27.69
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                3.02
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Diluted earnings per share | — | — | 
                                        
                                             
                                                12.27
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             | 
                                
                                    
                                        
                                             | 
                                
                                    — | — | 
| Equity-to-asset ratio | 
                                        
                                             
                                                0.152
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                0.139
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                0.119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     |