v3.26.1
Shareholder Report, Average Annual Return (Details)
6 Months Ended 12 Months Ended 60 Months Ended 90 Months Ended 120 Months Ended
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2026
C000002851          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Equity Income Fund - Class AAA        
C000243164          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Equity Income Fund - Class C        
Average Annual Return, Percent 2.92% 14.48% 7.09%   8.03%
C000061072          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Equity Income Fund - Class I        
C000002850          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Equity Income Fund - Class A        
Average Annual Return, Percent (1.62%) 9.83% 6.65%   8.22%
C000203681          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Global Financial Services Fund - Class A        
Average Annual Return, Percent (0.59%) 20.50% 14.90% 11.52%  
C000203683          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Global Financial Services Fund - Class C        
Average Annual Return, Percent 4.07% 25.82% 15.37% 11.52%  
C000203680          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Global Financial Services Fund - Class I        
C000203682          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Global Financial Services Fund - Class AAA        
C000002861          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Focused Growth and Income Fund - Class AAA        
C000002860          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Focused Growth and Income Fund - Class C        
Average Annual Return, Percent 4.62% 3.93% 5.47%   5.25%
C000061074          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Focused Growth and Income Fund - Class I        
C000002858          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Focused Growth and Income Fund - Class A        
Average Annual Return, Percent 0.16% 0.06% 5.34%   5.58%
C000002855          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Small Cap Growth Fund - Class AAA        
C000002857          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Small Cap Growth Fund - Class C        
Average Annual Return, Percent 2.03% 15.43% 7.01%   9.20%
C000061073          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Small Cap Growth Fund - Class I        
C000002854          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name The Gabelli Small Cap Growth Fund - Class A        
Average Annual Return, Percent (2.53%) 10.58% 6.55%   9.37%
Without Sales Load [Member] | C000002851          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.45% 16.61% 7.91%   8.86%
Without Sales Load [Member] | C000243164          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.92% 15.48% 7.09%   8.03%
Without Sales Load [Member] | C000061072          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.56% 16.86% 8.17%   9.13%
Without Sales Load [Member] | C000002850          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.38% 16.53% 7.92%   8.87%
Without Sales Load [Member] | C000203681          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.48% 27.85% 16.26% 12.41%  
Without Sales Load [Member] | C000203683          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.07% 26.82% 15.37% 11.52%  
Without Sales Load [Member] | C000203680          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.66% 28.22% 16.55% 12.65%  
Without Sales Load [Member] | C000203682          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.45% 27.83% 16.26% 12.37%  
Without Sales Load [Member] | C000002861          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.94% 5.64% 6.23%   6.02%
Without Sales Load [Member] | C000002860          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.62% 4.93% 5.47%   5.25%
Without Sales Load [Member] | C000061074          
Average Annual Return [Line Items]          
Average Annual Return, Percent 6.51% 6.65% 7.27%   6.69%
Without Sales Load [Member] | C000002858          
Average Annual Return [Line Items]          
Average Annual Return, Percent 6.27% 6.17% 6.60%   6.21%
Without Sales Load [Member] | C000002855          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.42% 17.33% 7.82%   10.02%
Without Sales Load [Member] | C000002857          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.03% 16.43% 7.01%   9.20%
Without Sales Load [Member] | C000061073          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.57% 17.65% 8.09%   10.30%
Without Sales Load [Member] | C000002854          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.42% 17.33% 7.82%   10.02%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06% 13.10%  
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06% 13.10%  
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06% 13.10%  
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06% 13.10%  
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
S&P 500 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (1.79%) 17.80% 12.06%   14.16%
Russell 2000 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.10% 25.72% 3.77%   9.88%
Russell 2000 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.10% 25.72% 3.77%   9.88%
Russell 2000 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.10% 25.72% 3.77%   9.88%
Russell 2000 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.10% 25.72% 3.77%   9.88%
Lipper Equity Income Fund Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.14% 13.51% 9.46%   10.60%
Lipper Equity Income Fund Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.14% 13.51% 9.46%   10.60%
Lipper Equity Income Fund Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.14% 13.51% 9.46%   10.60%
Lipper Equity Income Fund Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.14% 13.51% 9.46%   10.60%
MSCI World Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (2.49%) 13.38% 13.01% 11.30%  
S&P 500 Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (7.52%) 0.72% 9.72% 10.22%  
MSCI World Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (2.49%) 13.38% 13.01% 11.30%  
S&P 500 Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (7.52%) 0.72% 9.72% 10.22%  
MSCI World Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (2.49%) 13.38% 13.01% 11.30%  
S&P 500 Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (7.52%) 0.72% 9.72% 10.22%  
MSCI World Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (2.49%) 13.38% 13.01% 11.30%  
S&P 500 Financials Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent (7.52%) 0.72% 9.72% 10.22%  
S&P Midcap 400          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.19% 17.35% 6.92%   10.58%
S&P Midcap 400          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.19% 17.35% 6.92%   10.58%
S&P Midcap 400          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.19% 17.35% 6.92%   10.58%
S&P Midcap 400          
Average Annual Return [Line Items]          
Average Annual Return, Percent 4.19% 17.35% 6.92%   10.58%
S&P SmallCap 600 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.27% 20.50% 4.49%   9.90%
Lipper Small-Cap Core Funds Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.40% 17.94% 5.07%   9.66%
S&P SmallCap 600 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.27% 20.50% 4.49%   9.90%
Lipper Small-Cap Core Funds Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.40% 17.94% 5.07%   9.66%
S&P SmallCap 600 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.27% 20.50% 4.49%   9.90%
Lipper Small-Cap Core Funds Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.40% 17.94% 5.07%   9.66%
S&P SmallCap 600 Index          
Average Annual Return [Line Items]          
Average Annual Return, Percent 5.27% 20.50% 4.49%   9.90%
Lipper Small-Cap Core Funds Average          
Average Annual Return [Line Items]          
Average Annual Return, Percent 3.40% 17.94% 5.07%   9.66%