Alger Small Cap Growth Fund Investment Objectives and Goals - Class Z Shares [Member] - Alger Small Cap Growth 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 Small Cap Growth 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 Small Cap Growth Fund seeks long-term capital appreciation.