| 
                                Mar 2019
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                10,621,411
                             | 
                            
                            
                                1.25%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Dec 2018
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                14,517,461
                             | 
                            
                            
                                1.71%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Jun 2018
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                14,386,850
                             | 
                            
                            
                                1.69%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Mar 2018
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                11,295,397
                             | 
                            
                            
                                1.33%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Sep 2017
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                11,145,397
                             | 
                            
                            
                                1.31%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Jun 2017
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                10,856,122
                             | 
                            
                            
                                1.28%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Dec 2016
                             | 
                            
                                
                                    Baron Emerging Fund
                                
                             | 
                            
                                10,500,000
                             | 
                            
                            
                                1.24%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                        
                    
                        
                            
                                
                                    | 
                                     | 
                                    
                                        
                                         | 
                                    
                                    
                                        
                                         | 
                                    
                                
                                
                        
                        
                            | 
                                Sep 2016
                             | 
                            
                                
                                    Baron Emerging Markets Fund
                                
                             | 
                            
                                9,650,000
                             | 
                            
                            
                                1.14%
                             | 
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 | 
                            
                            
                                
                                    0
                                 | 
                                
                                    0.00%
                                 |