v3.26.3
Mid Cap Index Fund Investment Objectives and Goals - Mid Cap Index Fund
May 31, 2026
Prospectus [Line Items]  
Risk/Return [Heading] Fund Summary: Mid Cap Index Fund
Objective [Heading] <span style="color:#000000;font-family:Arial;font-size:12pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] The Fund seeks to provide growth of capital through investments primarily in a diversified portfolio of common stocks that, as a group, are expected to provide investment results closely corresponding to the performance of the S&P MidCap 400® Index (the “Index”).