Alger Responsible Investing Fund Investment Strategy - Class A C Shares [Member] - Alger Responsible Investing Fund	Oct. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	<span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategy</span>
Strategy Narrative [Text Block]	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 circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities of companies of any size with an environmental, social and governance (“ESG”) rating of average or above by a third-party ESG rating agency (an “ESG Rating Agency”) that also demonstrate, in the view of the Manager, promising growth potential. Equity securities include common or preferred stocks that are listed on U.S. or foreign exchanges. The Manager employs fundamental analysis to identify innovative and dynamic companies and uses an ESG Rating Agency’s ratings to consider how such stocks rank within an industry or sector based on a company’s conduct in offering products or services that promote positive environmental, social and/or governance policies, or have a positive impact in these areas, addressing concerns such as climate change, resource depletion, health and safety, employee relations and diversity, bribery and corruption, and fostering board diversity and structure. The Fund does not bar companies in any industries.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, consumer discretionary, and communication services sectors. For the purpose of categorizing companies, sectors are a broader category than industries and industries comprise sectors.The Fund may sell a stock when it reaches a target price, it fails to perform as expected, or other opportunities appear more attractive. As a result, the Fund may engage in active trading of portfolio 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.

Alger Responsible Investing Fund Investment Strategy - Class A C Shares [Member] - Alger Responsible Investing Fund

Oct. 31, 2025

<span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategy</span>

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 circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities of companies of any size with an environmental, social and governance (“ESG”) rating of average or above by a third-party ESG rating agency (an “ESG Rating Agency”) that also demonstrate, in the view of the Manager, promising growth potential. Equity securities include common or preferred stocks that are listed on U.S. or foreign exchanges. The Manager employs fundamental analysis to identify innovative and dynamic companies and uses an ESG Rating Agency’s ratings to consider how such stocks rank within an industry or sector based on a company’s conduct in offering products or services that promote positive environmental, social and/or governance policies, or have a positive impact in these areas, addressing concerns such as climate change, resource depletion, health and safety, employee relations and diversity, bribery and corruption, and fostering board diversity and structure. The Fund does not bar companies in any industries.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, consumer discretionary, and communication services sectors. For the purpose of categorizing companies, sectors are a broader category than industries and industries comprise sectors.The Fund may sell a stock when it reaches a target price, it fails to perform as expected, or other opportunities appear more attractive. As a result, the Fund may engage in active trading of portfolio 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.