Alger Capital Appreciation Fund Investment Risks - Class Z Shares [Member] - Alger Capital Appreciation Fund	Oct. 31, 2025
Investment Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment Risk – An investment in the Fund is subject to investment risk, including the possible loss of the entire principal amount that you invest.
Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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, trade disputes and changes in trade regulations, civil unrest, recessions, or other events could have a significant impact on the Fund and its investments.
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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.
Growth Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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.
Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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.
Information Technology Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	●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.
Consumer Discretionary Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	●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.
Communication Services Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	●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.
Privately Placed Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Privately Placed Securities Risk – A private placement is an offering of a company’s securities that is not registered with the Securities and Exchange Commission (the “SEC”) and is not offered to the public. The issuers of privately placed securities are not typically subject to the same oversight and regulatory requirements, including disclosure and other investor protection requirements, to which public issuers are subject, and there may be very little public information available about the issuers and their performance. The sale or transfer of privately placed securities may be limited or prohibited by contract or law and such investments are generally considered to be illiquid. Privately placed securities are generally fair valued as they are not traded frequently. The Fund may be required to hold such positions for several years, if not longer, regardless of valuation, which may cause the Fund to be less liquid. As a result, investments in private placements can result in substantial or complete losses.
Foreign Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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. Additionally, events and evolving conditions in certain markets or regions may alter the risk profile of investments tied to those markets or regions. This may cause investments tied to such markets or regions to become riskier or more volatile, even when investments in such markets or regions were perceived as comparatively stable historically. In addition, foreign companies with securities listed on U.S. exchanges may be delisted if they do not meet U.S. accounting standards and auditor oversight requirements, which may decrease the liquidity and value of the securities.
Cash Position Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s share price may go down, which means you could lose money.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	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.