Employees
| Concept | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 
|---|---|---|---|
| Employees | |||
| Metrics related to human capital diversity | |||
| Metrics of consolidated subsidiaries | |||
| Consolidated subsidiaries | 
                                                株式会社環境総合リサーチ
                                                
                                             | 
                                                株式会社日総建
                                                
                                             | 
                                                株式会社建設技研インターナショナル
                                                
                                             | 
| Ratio of female employees in managerial positions | 
                                                0.238
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.005
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Ratio of male employees taking childcare leave | |||
| All employees | 
                                                1.00
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.00
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.00
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |