Key Financial Data Of Group
| Concept | 
                                    
                                        2024-01-01 to 2024-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                                
                                    
                                        2023-07-01 to 2024-03-31  | 
                            
                                
                                    
                                        As at 2023-06-30  | 
                            
                                
                                    
                                        2022-07-01 to 2023-06-30  | 
                            
                                
                                    
                                        2023-01-01 to 2023-03-31  | 
                            
                                
                                    
                                        As at 2023-03-31  | 
                            
                                
                                    
                                        2022-07-01 to 2023-03-31  | 
                            
                        
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | — | — | 
                                        
                                             
                                                1,754,043,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                2,319,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,740,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Ordinary profit (loss) | — | — | 
                                        
                                             
                                                153,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                234,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                190,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Profit (loss) attributable to owners of parent | — | — | 
                                        
                                             
                                                107,064,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                114,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                98,911,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Comprehensive income | — | — | 
                                        
                                             
                                                308,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                106,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                29,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Net assets | — | 
                                        
                                             
                                                1,720,845,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                1,621,386,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,544,714,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Total assets | — | 
                                        
                                             
                                                4,324,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                3,811,386,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                3,698,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Basic earnings (loss) per share | 
                                        
                                             
                                                1.55
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                6.11
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                6.04
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2.36
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                5.17
                                                
                                             
                                        
                                     | 
                                
                            
| Diluted earnings per share | — | — | 
                                        
                                             | 
                                
                                    — | 
                                        
                                             | 
                                
                                    — | — | 
                                        
                                             | 
                                
                            
| Equity-to-asset ratio | — | 
                                        
                                             
                                                0.398
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                0.425
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                0.418
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — |