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Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName THE ALGER FUNDS
Prospectus Date rr_ProspectusDate Feb. 28, 2025
Class A C Shares | Alger Capital Appreciation Fund - AC  
Risk Return Abstract rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading <span style="color:#262626;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Alger Capital Appreciation Fund</span>
Objective [Heading] rr_ObjectiveHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Alger Capital Appreciation Fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Fund Fees and Expenses</span>
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and examples below.You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in Class A Shares of the Alger Family of Funds, including the Fund. More information about these and other discounts is available from your financial professional and in “Purchasing and Redeeming Fund Shares” on page 69 and in Appendix A – Waivers and Discounts Available from Intermediaries on page A-1 in the Fund’s Prospectus, and in the sections “Right of Accumulation (Class A Shares)” and “Letter of Intent (Class A)” beginning on page 38 of the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption <span style="color:#262626;font-family:Arial;font-size:9pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#262626;font-family:Arial;font-size:9pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text] rr_OperatingExpensesCaption <span style="color:#262626;font-family:Arial;font-size:9pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#262626;font-family:Arial;font-size:9pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 60.48% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 60.48%
Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock Purchases of $1 million or more of Class A Shares at net asset value may be subject to a contingent deferred sales charge of 1.00% on redemptions made within 12 months of purchase.
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts <span style="color:#262626;font-family:Arial;font-size:9pt;">You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least </span><span style="color:#262626;font-family:Arial;font-size:9pt;">$25,000</span><span style="color:#262626;font-family:Arial;font-size:9pt;"> in Class A Shares of the Alger Family of Funds, including the Fund.</span><span style="color:#262626;font-family:Arial;font-size:8pt;">The Fund and Fred Alger Management, LLC (the “Manager”) have adopted fee breakpoints for the Fund. The advisory fee for assets up to $2 billion is .81%, for assets between $2 billion and $3 billion is .65%, for assets between $3 billion and $4 billion is .60%, for assets between $4 billion and $5 billion is .55%, and for assets in excess of $5 billion is .45%. The actual rate paid as a percentage of average daily net assets for the year ended October 31, 2024 was .81%.</span>
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 25,000
Expense Example [Heading] rr_ExpenseExampleHeading <span style="color:#0064FA;font-family:Arial;font-size:9pt;font-weight:bold;">Example</span>
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The following examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The examples assume that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, No Redemption, By Year, Caption [Text] rr_ExpenseExampleNoRedemptionByYearCaption <span style="color:#262626;font-family:Arial;font-size:8pt;font-weight:bold;">You would pay the following expenses if you did not redeem your shares:</span>
Strategy [Heading] rr_StrategyHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategy</span>
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The Manager believes companies undergoing Positive Dynamic Change offer the best opportunities. Positive Dynamic Change refers to companies realizing High Unit Volume Growth or companies undergoing Positive Lifecycle Change. High Unit Volume Growth companies are traditional growth companies experiencing, for example, rapidly growing demand or market dominance. Positive Lifecycle Change companies are, for example, companies benefitting from new regulations, a new product innovation or new management.Under normal market circumstances, the Fund invests at least 85% of its net assets, plus any borrowings for investment purposes, in equity securities of companies of any market capitalization that the Manager believes demonstrate promising growth potential. Equity securities include common or preferred stocks that are listed on U.S. or foreign exchanges.The Fund may sell a stock when it reaches a target price, it fails to perform as expected, or other opportunities appear more attractive.The Fund may invest a significant portion of its assets in securities of companies conducting business within a single sector, as defined by third party sources, including, but not limited to, the information technology, health care, consumer discretionary, and communication services sectors.The Fund can invest in foreign securities.The Fund may invest in cash (and cash equivalents) when the Fund is unable to find enough attractive long-term investments to meet its investment objective, to meet redemptions and/or when the Manager believes it is advisable to do so during times of short-term market volatility. During these times, cash (and cash equivalents) will not exceed 15% of the Fund’s net assets.
Risk [Heading] rr_RiskHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</span>
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Performance</span>
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The following bar chart and the table beneath it provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns for the indicated periods compare with those of an appropriate broad-based securities market index that represents the overall domestic equity market and a more narrowly based index that reflects the market sectors in which the Fund invests. Performance in the bar chart does not reflect the effect of the sales charge imposed on purchases of Class A Shares of the Fund. If the bar chart reflected the applicable sales charges, returns would be less than those shown.The Fund’s past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. Updated performance information is available on the Fund’s website www.alger.com. The broad-based securities market index used for comparison with the Fund’s performance changed from the Russell 1000 Growth Index to the S&P 500 Index to comply with new regulations that require the Fund’s broad-based securities market index to reflect the overall market in which the Fund may invest. The Fund’s previous broad-based securities market index, the Russell 1000 Growth Index, which the Manager believes more closely reflects the market segments in which the Fund invests, is included as an additional index.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns <span style="color:#262626;font-family:Arial;font-size:9pt;">The following bar chart and the table beneath it provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns for the indicated periods compare with those of an appropriate broad-based securities market index that represents the overall domestic equity market</span><span style="color:#262626;font-family:Arial;font-size:9pt;line-height:11pt;"> </span><span style="color:#262626;font-family:Arial;font-size:9pt;">and a more narrowly based index that reflects the market sectors in which the Fund invests. </span>
Performance Additional Market Index [Text] rr_PerformanceAdditionalMarketIndex <span style="color:#262626;font-family:Arial;font-size:9pt;">The Fund’s previous broad-based securities market index, the Russell 1000 </span><span style="color:#262626;font-family:Arial;font-size:9pt;">Growth Index, which the Manager believes more closely reflects the market segments in which the Fund invests, is included as an additional index.</span>
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress <span style="color:#262626;font-family:Arial;font-size:9pt;">www.alger.com</span>
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture <span style="color:#262626;font-family:Arial;font-size:9pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.</span>
Bar Chart [Heading] rr_BarChartHeading <span style="color:#262626;font-family:Arial;font-size:10pt;font-weight:bold;">Annual Total Return for Class A Shares</span><span style="color:#262626;font-family:Arial;font-size:10pt;line-height:12pt;"> </span><span style="color:#262626;font-family:Arial;font-size:10pt;font-style:italic;">as of December 31 (%)</span>
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads <span style="color:#262626;font-family:Arial;font-size:9pt;">Performance in the bar chart does not </span><span style="color:#262626;font-family:Arial;font-size:9pt;">reflect the effect of the sales charge imposed on purchases of Class A Shares of the Fund. If the bar chart reflected the applicable sales charges, returns would be less than those shown.</span>
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock Best Quarter:Q2 202028.20%Worst Quarter:Q2 2022-24.61%
Performance Table Heading rr_PerformanceTableHeading <span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Average Annual Total Return as of December 31, 2024</span>
Performance Table Market Index Changed rr_PerformanceTableMarketIndexChanged <span style="color:#262626;font-family:Arial;font-size:9pt;">The broad-based securities market index used for comparison with the Fund’s performance changed from the Russell 1000 Growth Index to the S&P 500 Index to comply with new regulations that require the Fund’s broad-based securities market index to reflect the overall market in which the Fund may invest. </span>
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate <span style="color:#262626;font-family:Arial;font-size:9pt;">after-tax returns are calculated using the historical highest individual federal marginal income tax rates and </span><span style="color:#262626;font-family:Arial;font-size:9pt;">do not reflect the impact of state and local taxes.</span>
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred <span style="color:#262626;font-family:Arial;font-size:9pt;">Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown may not be relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.</span>
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown <span style="color:#262626;font-family:Arial;font-size:9pt;">After-tax returns for Class C Shares, which are not shown, will vary from those shown for Class A Shares.</span>
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock In the foregoing table, after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown may not be relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.After-tax returns for Class C Shares, which are not shown, will vary from those shown for Class A Shares.
Class A C Shares | Alger Capital Appreciation Fund - AC | Risk Lose Money [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock The Fund’s share price may go down, which means you could lose money.
Class A C Shares | Alger Capital Appreciation Fund - AC | Risk Not Insured Depository Institution [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Class A C Shares | Alger Capital Appreciation Fund - AC | Investment Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Investment Risk – An investment in the Fund is subject to investment risk, including the possible loss of the entire principal amount that you invest.
Class A C Shares | Alger Capital Appreciation Fund - AC | Market Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Market Risk – Your investment in Fund shares represents an indirect investment in the securities owned by the Fund. The value of these securities, like other investments, may move up or down, sometimes rapidly and unpredictably. Your Fund shares at any point in time may be worth less than what you invested, even after taking into account the reinvestment of Fund dividends and distributions. Local, regional or global events such as environmental or natural disasters, war, terrorism, pandemics, outbreaks of infectious diseases, and similar public health threats, recessions, or other events could have a significant impact on the Fund and its investments.
Class A C Shares | Alger Capital Appreciation Fund - AC | Equity Securities Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Equity Securities Risk – As with any fund that invests in stocks, your investment will fluctuate in value, and the loss of your investment is a risk of investing. The Fund’s price per share will fluctuate due to changes in the market prices of its investments. Also, the Fund’s investments may not grow as fast as the rate of inflation and stocks tend to be more volatile than some other investments you could make, such as bonds.
Class A C Shares | Alger Capital Appreciation Fund - AC | Growth Securities Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Growth Securities Risk – Prices of growth stocks tend to be higher in relation to their companies’ earnings and may be more sensitive to market, political and economic developments than other stocks, making their prices more volatile. An investment in the Fund may be better suited to investors who seek long-term capital growth and can tolerate fluctuations in their investment’s value.
Class A C Shares | Alger Capital Appreciation Fund - AC | Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Sector Risk – The Fund may have a significant portion of its assets invested in securities of companies conducting business within a single sector, as defined by third party sources. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than a fund that has a more diversified portfolio. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.
Class A C Shares | Alger Capital Appreciation Fund - AC | Information Technology Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Information Technology Sector Risk – The Fund may have a significant portion of its assets invested in securities of technology-related companies. Therefore, the Fund may be more susceptible to particular risks that may affect companies in the information technology sector and technology-related sectors than if it were invested in a wider variety of companies in unrelated sectors. At times, the performance of such companies will lag the performance of other industries or the broader market as a whole. Certain technology related companies may face special risks that their products or services may not prove to be commercially successful. Technology related companies are also strongly affected by worldwide scientific or technological developments. As a result, their products may rapidly become obsolete. Such companies are also often subject to governmental regulation and may, therefore, be adversely affected by governmental policies. These factors may lead to limited earnings and/or failing profit margins. As a result, the value of technology related companies’ securities may fall or fail to rise. Many technology related companies’ securities have historically been more volatile than other securities, especially over the short term.
Class A C Shares | Alger Capital Appreciation Fund - AC | Health Care Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Health Care Sector Risk – The Fund may have a significant portion of its assets invested in securities of healthcare companies. At times, the performance of healthcare companies will lag the performance of other industries or the broader market as a whole, and the performance of such companies may be more volatile. Healthcare companies may also be significantly affected by intense competition, aggressive pricing, government regulation, technological innovations, product obsolescence, patent considerations, product compatibility and consumer preferences.
Class A C Shares | Alger Capital Appreciation Fund - AC | Consumer Discretionary Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Consumer Discretionary Sector Risk – The consumer discretionary sector may be affected by changes in domestic and international economies, exchange and interest rates, competition, consumers’ disposable income, consumer preferences, social trends and marketing campaigns.
Class A C Shares | Alger Capital Appreciation Fund - AC | Communication Services Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Communication Services Sector Risk – Communication services companies are particularly vulnerable to the potential obsolescence of products and services due to technological advancement and the innovation of competitors. Companies in the communication services sector may also be affected by other competitive pressures, such as pricing competition, as well as research and development costs, substantial capital requirements and government regulation. Additionally, fluctuating domestic and international demand, shifting demographics and often unpredictable changes in consumer tastes can drastically affect a communication services company’s profitability. While all companies may be susceptible to network security breaches, certain companies in the communication services sector may be particular targets of hacking and potential theft of proprietary or consumer information or disruptions in service, which could have a material adverse effect on their businesses.
Class A C Shares | Alger Capital Appreciation Fund - AC | Foreign Securities Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Foreign Securities Risk – The Fund’s performance will be influenced by political, social and economic factors affecting investments in foreign companies. Special risks associated with investments in foreign companies include exposure to currency fluctuations, lack of liquidity, potential for market manipulation, less developed or less efficient trading markets, limited access to reliable capital, lack of comprehensive company information, political instability, differing audit, regulatory, and legal standards and lack of financial reporting standards.
Class A C Shares | Alger Capital Appreciation Fund - AC | Cash Position Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Cash Position Risk – At times, the Fund may hold up to 15% of its net assets in cash (and cash equivalents), which may underperform relative to equity securities.
Class A C Shares | Alger Capital Appreciation Fund - AC | Class A  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum deferred sales charge (load) as a % of purchase price or redemption proceeds, whichever is lower rr_MaximumDeferredSalesChargeOverOfferingPrice none [1]
Advisory Fees rr_ManagementFeesOverAssets 0.81% [2]
Distribution and/or Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.20%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.26%
1 Year rr_ExpenseExampleYear01 $ 647
3 Years rr_ExpenseExampleYear03 904
5 Years rr_ExpenseExampleYear05 1,180
10 Years rr_ExpenseExampleYear10 $ 1,968
2015 rr_AnnualReturn2015 6.25%
2016 rr_AnnualReturn2016 0.33%
2017 rr_AnnualReturn2017 31.22%
2018 rr_AnnualReturn2018 (1.00%)
2019 rr_AnnualReturn2019 33.14%
2020 rr_AnnualReturn2020 41.63%
2021 rr_AnnualReturn2021 17.58%
2022 rr_AnnualReturn2022 (36.82%)
2023 rr_AnnualReturn2023 43.04%
2024 rr_AnnualReturn2024 49.71%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel <span style="color:#262626;font-family:Arial;font-size:8pt;font-weight:bold;">Best Quarter:</span>
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 28.20%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel <span style="color:#262626;font-family:Arial;font-size:8pt;font-weight:bold;">Worst Quarter:</span>
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2022
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (24.61%)
1 Year rr_AverageAnnualReturnYear01 41.84%
5 Years rr_AverageAnnualReturnYear05 16.38%
10 Years rr_AverageAnnualReturnYear10 14.68%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 31, 1996
Class A C Shares | Alger Capital Appreciation Fund - AC | Class C  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) as a % of purchase price or redemption proceeds, whichever is lower rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Advisory Fees rr_ManagementFeesOverAssets 0.81% [2]
Distribution and/or Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.97%
1 Year rr_ExpenseExampleYear01 $ 300
3 Years rr_ExpenseExampleYear03 618
5 Years rr_ExpenseExampleYear05 1,062
10 Years rr_ExpenseExampleYear10 2,296
1 Year rr_ExpenseExampleNoRedemptionYear01 200
3 Years rr_ExpenseExampleNoRedemptionYear03 618
5 Years rr_ExpenseExampleNoRedemptionYear05 1,062
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,296
1 Year rr_AverageAnnualReturnYear01 47.80%
5 Years rr_AverageAnnualReturnYear05 16.79%
10 Years rr_AverageAnnualReturnYear10 14.62%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 31, 1997
Class A C Shares | Alger Capital Appreciation Fund - AC | Return After Taxes on Distributions | Class A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 37.87%
5 Years rr_AverageAnnualReturnYear05 13.19%
10 Years rr_AverageAnnualReturnYear10 12.21%
Class A C Shares | Alger Capital Appreciation Fund - AC | Return After Taxes on Distributions and Sale of Shares | Class A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 27.40%
5 Years rr_AverageAnnualReturnYear05 12.47%
10 Years rr_AverageAnnualReturnYear10 11.52%
Class A C Shares | Alger Capital Appreciation Fund - AC | Russell 1000 Growth Index (reflects no deductions for fees, expenses or taxes)  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 33.36%
5 Years rr_AverageAnnualReturnYear05 18.96%
10 Years rr_AverageAnnualReturnYear10 16.78%
Class A C Shares | Alger Capital Appreciation Fund - AC | S&P 500 Index (reflects no deductions for fees, expenses or taxes)  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 25.02%
5 Years rr_AverageAnnualReturnYear05 14.53%
10 Years rr_AverageAnnualReturnYear10 13.10%
[1] Purchases of $1 million or more of Class A Shares at net asset value may be subject to a contingent deferred sales charge of 1.00% on redemptions made within 12 months of purchase.
[2] The Fund and Fred Alger Management, LLC (the “Manager”) have adopted fee breakpoints for the Fund. The advisory fee for assets up to $2 billion is .81%, for assets between $2 billion and $3 billion is .65%, for assets between $3 billion and $4 billion is .60%, for assets between $4 billion and $5 billion is .55%, and for assets in excess of $5 billion is .45%. The actual rate paid as a percentage of average daily net assets for the year ended October 31, 2024 was .81%.