Employees
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 
|---|---|---|---|---|
| Employees | ||||
| Metrics related to human capital diversity | ||||
| Metrics of consolidated subsidiaries | ||||
| Consolidated subsidiaries | 
                                                熊本銀行
                                                
                                             | 
                                                福岡中央銀行
                                                
                                             | 
                                                福岡銀行
                                                
                                             | 
                                                十八親和銀行
                                                
                                             | 
| Ratio of female employees in managerial positions | 
                                                0.283
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.205
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.194
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.188
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Ratio of male employees taking childcare leave | ||||
| All employees | 
                                                0.931
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.000
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.981
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Differences in wages between male and female employees | ||||
| All employees | 
                                                0.514
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.557
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.393
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.446
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Regular employees | 
                                                0.718
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.643
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.622
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.678
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Non-regular employees | 
                                                0.431
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.524
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.359
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.533
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |