Major Shareholders
| Concept | 
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                                
                                    
                                        As at 2024-01-31  | 
                            
                        
|---|---|---|---|---|---|---|---|---|---|---|---|
| Major shareholders | |||||||||||
| Major shareholders | |||||||||||
| Name | 
                                        
                                             
                                                日本エコシステム㈱
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                瀧上工業㈱
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                岐阜信用金庫
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                太洋基礎工業従業員持株会
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱ナガワ
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                豊 住   清
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                太洋基礎工業取引先持株会
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                徳倉建設㈱
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱愛知銀行
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱三東工業社
                                                
                                             
                                        
                                     | 
                                
                            
| Address | 
                                        
                                             
                                                一宮市本町2丁目2番11号
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                半田市神明町1丁目1番地
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                岐阜県岐阜市神田町6丁目11番地
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                名古屋市中川区柳森町107番地
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                千代田区丸の内1丁目4番1号
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                名古屋市守山区
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                名古屋市中川区柳森町107番地
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                名古屋市中区錦3丁目13番5号
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                名古屋市中区栄3丁目14番12号
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                滋賀県栗東市上鈎480番地
                                                
                                             
                                        
                                     | 
                                
                            
| Number of shares held | 
                                        
                                             
                                                54,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                62,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                65,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                53,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                47,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                1,179,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                567,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                121,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                57,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                90,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                60,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Shareholding ratio (excluding treasury shares) | 
                                        
                                             
                                                0.0271
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0314
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0329
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0267
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0237
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.5927
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.2853
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0612
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0290
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0452
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0.0302
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     |