v3.26.1
Shareholder Report, Line Graph (Details) - USD ($)
 6 Months Ended 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Jun. 30, 2016
Jun. 30, 2026
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2022
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2026
C000002886                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   The Gabelli ABC Fund - Class I                    
C000050409                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   The Gabelli ABC Fund - Advisor Class                    
S&P 500 Index                        
Account Value [Line Items]                        
Accumulated Value $ 10,000   $ 11,790 $ 13,484 $ 14,889 $ 16,007 $ 22,537 $ 20,143 $ 24,090 $ 30,006 $ 34,555 $ 42,268
S&P 500 Index                        
Account Value [Line Items]                        
Accumulated Value 10,000   11,790 13,484 14,889 16,007 22,537 20,143 24,090 30,006 34,555 42,268
ICE BofA 3 Month U.S. Treasury Bill Index                        
Account Value [Line Items]                        
Accumulated Value 10,000   10,049 10,186 10,421 10,592 10,601 10,619 11,001 11,595 12,137 12,603
Lipper U.S. Treasury Money-Market Fund Average                        
Account Value [Line Items]                        
Accumulated Value 10,000   10,016 10,105 10,301 10,419 10,421 10,431 10,791 11,346 11,851 12,283
ICE BofA 3 Month U.S. Treasury Bill Index                        
Account Value [Line Items]                        
Accumulated Value 10,000   10,049 10,186 10,421 10,592 10,601 10,619 11,001 11,595 12,137 12,603
Lipper U.S. Treasury Money-Market Fund Average                        
Account Value [Line Items]                        
Accumulated Value $ 10,000   $ 10,016 $ 10,105 $ 10,301 $ 10,419 $ 10,421 $ 10,431 $ 10,791 $ 11,346 $ 11,851 $ 12,283