Alger Health Sciences Fund Investment Objectives and Goals - Class A C Shares [Member] - Alger Health Sciences Fund	Oct. 31, 2025
Prospectus [Line Items]
Risk/Return [Heading]	<span style="color:#262626;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Alger Health Sciences Fund</span>
Objective [Heading]	<span style="color:#0064FA;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	Alger Health Sciences Fund seeks long-term capital appreciation.