v3.25.4
Average Annual Total Returns
 12 Months Ended 58 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Russell 3000® Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 17.15%   13.15% 14.29%
Russell Midcap® Growth Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 8.66%   6.65% 12.49%
Russell 2000® Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 12.81%   6.09% 9.62%
S&P 500® Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 17.88% 13.68% 14.42% 14.82%
Russell Midcap® Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 10.60%   8.67% 11.01%
Russell 1000® Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 17.37%   13.59% 14.59%
Russell 1000® Value Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 15.91%   11.33% 10.53%
75/25 Blended DJIA/Treasury Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 12.25%   9.64% 10.52%
Dow Jones Industrial Average (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 14.92%   11.58% 13.11%
50/50 Blended DJIA/Treasury Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 9.67%   7.27% 7.77%
S&P 500® Energy Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 8.67%   23.78% 8.32%
Alerian US Midstream Energy Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 2.73%   28.23% 12.92%
AGA Stock Index (reflects no deduction forfees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 11.24%   12.65% 10.18%
Russell/Nomura Total Market Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 27.51%   7.23% 8.12%
TOPIX (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 25.79%   7.02% 7.92%
Russell/Nomura Small Cap Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 29.53%   5.96% 7.07%
Russell 1000® Index Financials (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 18.65%   16.79% 15.03%
Russell 2000® Index Financials (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 7.85%   9.16% 8.85%
Nasdaq Composite Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 21.14%   13.35% 17.66%
S&P 500® Equal Weight Index (reflects no deduction for fees, expenses, or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent 11.43% 8.34%    
Hennessy Energy Transition Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent [1] 12.48%   24.87% 9.11%
Hennessy Energy Transition Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent [1] 12.34%   23.68% 8.59%
Hennessy Energy Transition Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent [1] 7.49%   19.87% 7.18%
Hennessy Energy Transition Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 12.86%   25.30% 9.43%
Hennessy Midstream Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent [2] (0.74%)   23.86% 7.38%
Hennessy Midstream Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent [2] (1.76%)   22.99% 6.96%
Hennessy Midstream Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent [2] 0.32%   19.57% 5.91%
Hennessy Midstream Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent (0.47%)   24.17% 7.65%
Hennessy Technology Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 15.38%   9.00% 13.11%
Hennessy Technology Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 9.45%   5.79% 10.30%
Hennessy Technology Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 11.39%   6.08% 9.79%
Hennessy Technology Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 15.61%   9.27% 13.40%
Hennessy Sustainable ETF [Member]        
Prospectus [Line Items]        
Average Annual Return, Percent 10.18% 6.69%    
Performance Inception Date   Mar. 15, 2021    
Hennessy Sustainable ETF [Member] | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 9.91% 6.53%    
Hennessy Sustainable ETF [Member] | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 6.21% 5.23%    
Hennessy Cornerstone Growth Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 4.78%   15.11% 11.08%
Hennessy Cornerstone Growth Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 4.78%   13.08% 9.86%
Hennessy Cornerstone Growth Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 2.83%   11.78% 8.88%
Hennessy Cornerstone Growth Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 5.09%   15.49% 11.44%
Hennessy Focus Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 26.73%   11.65% 10.94%
Hennessy Focus Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 16.87%   6.63% 7.01%
Hennessy Focus Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 22.83%   8.51% 8.12%
Hennessy Focus Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 27.22%   12.07% 11.35%
Hennessy Cornerstone Mid Cap 30 Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 2.68%   18.72% 12.74%
Hennessy Cornerstone Mid Cap 30 Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 2.51%   16.16% 10.31%
Hennessy Cornerstone Mid Cap 30 Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 1.71%   14.71% 9.73%
Hennessy Cornerstone Mid Cap 30 Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 3.04%   19.16% 13.15%
Hennessy Cornerstone Large Growth Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 7.41%   9.76% 10.11%
Hennessy Cornerstone Large Growth Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 5.95%   7.54% 8.12%
Hennessy Cornerstone Large Growth Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 5.45%   7.46% 7.86%
Hennessy Cornerstone Large Growth Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 7.70%   10.08% 10.42%
Hennessy Cornerstone Value Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 18.27%   13.59% 10.48%
Hennessy Cornerstone Value Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 16.30%   12.02% 8.61%
Hennessy Cornerstone Value Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 12.21%   10.67% 8.05%
Hennessy Cornerstone Value Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 18.60%   13.85% 10.73%
Hennessy Total Return Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 14.29%   7.57% 6.84%
Hennessy Total Return Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 13.68%   6.47% 5.49%
Hennessy Total Return Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 8.86%   5.79% 5.22%
Hennessy Equity and Income Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 6.73%   5.49% 6.60%
Hennessy Equity and Income Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 4.00%   3.46% 4.65%
Hennessy Equity and Income Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 5.94%   4.15% 4.99%
Hennessy Equity and Income Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 7.24%   5.88% 7.01%
Hennessy Balanced Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 9.89%   4.96% 4.84%
Hennessy Balanced Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 9.34%   4.11% 3.78%
Hennessy Balanced Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 6.15%   3.74% 3.66%
Hennessy Gas Utility Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 10.40%   11.90% 9.13%
Hennessy Gas Utility Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 7.55%   9.62% 7.13%
Hennessy Gas Utility Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 8.22%   9.14% 7.00%
Hennessy Gas Utility Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 10.70%   12.24% 9.43%
Hennessy Japan Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 14.50%   2.34% 8.60%
Hennessy Japan Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 10.12%   1.00% 7.91%
Hennessy Japan Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 9.57%   1.53% 6.92%
Hennessy Japan Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 14.88%   2.72% 9.03%
Hennessy Japan Small Cap Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 28.89%   5.29% 9.60%
Hennessy Japan Small Cap Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 25.33%   4.58% 9.06%
Hennessy Japan Small Cap Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 19.78%   4.23% 7.95%
Hennessy Japan Small Cap Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 29.42%   5.71% 10.01%
Hennessy Large Cap Financial Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 22.00%   7.90% 10.36%
Hennessy Large Cap Financial Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 19.85%   6.80% 9.59%
Hennessy Large Cap Financial Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 14.53%   6.05% 8.40%
Hennessy Large Cap Financial Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 22.41%   8.26% 10.75%
Hennessy Small Cap Financial Fund - Investor Class        
Prospectus [Line Items]        
Average Annual Return, Percent 12.78%   10.64% 8.61%
Hennessy Small Cap Financial Fund - Investor Class | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 10.13%   9.10% 7.08%
Hennessy Small Cap Financial Fund - Investor Class | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 9.49%   8.32% 6.70%
Hennessy Small Cap Financial Fund - Institutional Class        
Prospectus [Line Items]        
Average Annual Return, Percent 13.17%   11.03% 8.99%
[1] Prior to the reorganization that took place on October 26, 2018, Investor Class shares of the Fund were subject to a sales charge (load) on purchases. In connection with the reorganization, performance information has been restated to reflect the removal of the sales load.
[2] Prior to the reorganization that took place on October 26, 2018, Investor Class shares of the Fund were subject to a sales charge (load) on purchases. In connection with the reorganization, performance information has been restated to reflect the removal of the sales load.