| 
                Dodge & Cox Stock Fund
             | 
                        
                Dec 31, 2017
             | 
                        
                37.3M
             | 
                        
                1.0B
             | 
                        
                8.3%
             | 
                    
                
                        | 
                Vanguard/Wellington Fund Inc.
             | 
                        
                Feb 28, 2018
             | 
                        
                32.3M
             | 
                        
                884.2M
             | 
                        
                7.2%
             | 
                    
                
                        | 
                Vanguard/Primecap Fund
             | 
                        
                Mar 31, 2018
             | 
                        
                24.5M
             | 
                        
                680.3M
             | 
                        
                5.5%
             | 
                    
                
                        | 
                Primecap Odyssey Stock Fund
             | 
                        
                Jun 30, 2018
             | 
                        
                8.0M
             | 
                        
                239.7M
             | 
                        
                1.8%
             | 
                    
                
                        | 
                Harbor Capital Appreciation Fund
             | 
                        
                Jun 30, 2018
             | 
                        
                6.8M
             | 
                        
                203.1M
             | 
                        
                1.5%
             | 
                    
                
                        | 
                Vanguard Fenway Fds-Primecap Core Fund
             | 
                        
                Mar 31, 2018
             | 
                        
                6.5M
             | 
                        
                181.6M
             | 
                        
                1.5%
             | 
                    
                
                        | 
                Dodge & Cox Balanced Fund
             | 
                        
                Dec 31, 2017
             | 
                        
                5.9M
             | 
                        
                164.0M
             | 
                        
                1.3%
             | 
                    
                
                        | 
                Washington Mutual Investors Fund
             | 
                        
                Jun 30, 2018
             | 
                        
                5.7M
             | 
                        
                170.7M
             | 
                        
                1.3%
             | 
                    
                
                        | 
                American Mutual Fund Inc
             | 
                        
                Jun 30, 2018
             | 
                        
                4.5M
             | 
                        
                134.9M
             | 
                        
                1.0%
             | 
                    
                
                        | 
                Price (T.Rowe) International Value Equity Fund
             | 
                        
                Jun 30, 2018
             | 
                        
                4.4M
             | 
                        
                130.8M
             | 
                        
                1.0%
             |