v3.25.4
Average Annual Total Returns
 12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
TETON WESTWOOD MIGHTY MITES FUND CLASS AAA      
Prospectus [Line Items]      
Average Annual Return, Percent 11.38% 6.33% 7.82%
TETON WESTWOOD MIGHTY MITES FUND CLASS AAA | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 6.33% 2.14% 4.98%
TETON WESTWOOD MIGHTY MITES FUND CLASS AAA | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 10.14% 4.54% 5.95%
TETON WESTWOOD MIGHTY MITES FUND CLASS A      
Prospectus [Line Items]      
Average Annual Return, Percent 6.95% 5.47% 7.26%
TETON WESTWOOD MIGHTY MITES FUND CLASS C      
Prospectus [Line Items]      
Average Annual Return, Percent 9.55% 5.53% 7.02%
TETON WESTWOOD MIGHTY MITES FUND Class I      
Prospectus [Line Items]      
Average Annual Return, Percent 11.75% 6.60% 8.10%
TETON WESTWOOD MIGHTY MITES FUND Class I | Russell 2000 Index      
Prospectus [Line Items]      
Average Annual Return, Percent 12.81% 6.09% 9.62%
TETON WESTWOOD MIGHTY MITES FUND Class I | Dow Jones U.S. Micro-cap Total Stock Market Index      
Prospectus [Line Items]      
Average Annual Return, Percent 13.96% 2.20% 6.74%
Keeley Small Cap Fund CLASS AAA      
Prospectus [Line Items]      
Average Annual Return, Percent 17.05% 11.65% 12.43%
Keeley Small Cap Fund CLASS AAA | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 15.05% 9.61% 10.50%
Keeley Small Cap Fund CLASS AAA | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 11.45% 9.06% 9.86%
Keeley Small Cap Fund CLASS A      
Prospectus [Line Items]      
Average Annual Return, Percent 12.37% 10.73% 11.84%
Keeley Small Cap Fund CLASS C      
Prospectus [Line Items]      
Average Annual Return, Percent 15.11% 10.80% 11.59%
Keeley Small Cap Fund Class I      
Prospectus [Line Items]      
Average Annual Return, Percent 17.28% 11.92% 12.71%
Keeley Small Cap Fund Class I | Russell 2000 Index      
Prospectus [Line Items]      
Average Annual Return, Percent 12.81% 6.09% 9.62%
Keeley Small Cap Fund Class I | Russell 2000 Value Index      
Prospectus [Line Items]      
Average Annual Return, Percent 12.59% 8.88% 9.27%
TETON Convertible Securities Fund CLASS AAA      
Prospectus [Line Items]      
Average Annual Return, Percent 17.16% 1.95% 8.00%
TETON Convertible Securities Fund CLASS AAA | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 13.34% (0.27%) 6.24%
TETON Convertible Securities Fund CLASS AAA | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 10.32% 0.78% 5.86%
TETON Convertible Securities Fund CLASS A      
Prospectus [Line Items]      
Average Annual Return, Percent 12.50% 1.12% 7.43%
TETON Convertible Securities Fund CLASS C      
Prospectus [Line Items]      
Average Annual Return, Percent 15.36% 1.19% 7.19%
TETON Convertible Securities Fund Class I      
Prospectus [Line Items]      
Average Annual Return, Percent 17.50% 2.20% 8.28%
TETON Convertible Securities Fund Class I | ICE Bank of America Merrill Lynch U.S. Convertibles Index      
Prospectus [Line Items]      
Average Annual Return, Percent 17.88% 5.05% 11.21%
TETON Convertible Securities Fund Class I | Standard & Poor’s 500 Index      
Prospectus [Line Items]      
Average Annual Return, Percent 17.88% 14.42% 14.82%
TETON WESTWOOD EQUITY FUND CLASS AAA      
Prospectus [Line Items]      
Average Annual Return, Percent 4.91% 7.11% 8.53%
TETON WESTWOOD EQUITY FUND CLASS AAA | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 1.68% 4.58% 6.07%
TETON WESTWOOD EQUITY FUND CLASS AAA | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 5.19% 5.33% 6.46%
TETON WESTWOOD EQUITY FUND CLASS A      
Prospectus [Line Items]      
Average Annual Return, Percent 0.80% 6.25% 7.96%
TETON WESTWOOD EQUITY FUND CLASS C      
Prospectus [Line Items]      
Average Annual Return, Percent 19.44% 9.42% 9.29%
TETON WESTWOOD EQUITY FUND Class I      
Prospectus [Line Items]      
Average Annual Return, Percent 5.16% 7.38% 8.80%
TETON WESTWOOD EQUITY FUND Class I | S&P 500 Index      
Prospectus [Line Items]      
Average Annual Return, Percent 17.88% 14.42% 14.82%
TETON WESTWOOD BALANCED FUND CLASS AAA      
Prospectus [Line Items]      
Average Annual Return, Percent 7.78% 5.47% 6.65%
TETON WESTWOOD BALANCED FUND CLASS AAA | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 4.37% 3.20% 4.56%
TETON WESTWOOD BALANCED FUND CLASS AAA | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 6.87% 3.96% 4.95%
TETON WESTWOOD BALANCED FUND CLASS A      
Prospectus [Line Items]      
Average Annual Return, Percent 3.43% 4.63% 6.09%
TETON WESTWOOD BALANCED FUND CLASS C      
Prospectus [Line Items]      
Average Annual Return, Percent 6.02% 4.69% 5.85%
TETON WESTWOOD BALANCED FUND Class I      
Prospectus [Line Items]      
Average Annual Return, Percent 8.04% 5.74% 6.91%
TETON WESTWOOD BALANCED FUND Class I | S&P 500 Index      
Prospectus [Line Items]      
Average Annual Return, Percent 17.88% 14.42% 14.82%
TETON WESTWOOD BALANCED FUND Class I | Bloomberg Barclays Government/Credit Bond Index      
Prospectus [Line Items]      
Average Annual Return, Percent 6.88% (0.59%) 2.16%
TETON WESTWOOD BALANCED FUND Class I | 60% S&P 500 Index and 40% Barclays Government/Credit Bond Index      
Prospectus [Line Items]      
Average Annual Return, Percent 13.48% 8.42% 9.76%