S000010792 [Member] Investment Strategy - S000010792 [Member]	Feb. 28, 2026
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of companies that have market capitalizations in the range of the companies in the Russell Midcap® Value Index (the Capitalization Index), which ranged between $81.5 million and $251 billion as of May 31, 2026, that the Fund’s investment manager believes are undervalued and have the potential for long-term growth. The market capitalization range and composition of companies in the Capitalization Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund may continue to hold a security even if the company’s market capitalization is no longer within the range of the Capitalization Index. Under normal circumstances, the Fund also invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of “value” companies. The Fund considers “value” companies to be those companies that are either constituents of an index constructed by a third party to identify companies with various characteristics of value companies, or that have a higher book-to-price (B/P) ratio than the median ranked stock within the company’s GICS sector, have a higher EBITDA/EV (earnings before interest, taxes, depreciation and amortization-to-enterprise value) or have a lower price-to-earnings ratio than the median ranked stock within the company’s GICS sector. The third-party broad-based index currently used to identify value companies is the Russell 3000® Value Index, although the Fund may change the referenced index without prior notice. The Fund may invest up to 20% of its total assets in foreign securities. The Fund normally invests in common stocks and also may invest in real estate investment trusts. The Fund may at times emphasize one or more sectors in selecting its investments, including the financials and industrials sectors. The Fund may hold a small number of securities, consistent with its value investment approach. Generally, the Fund anticipates holding between 30 and 50 securities in its portfolio; however, the Fund may hold, at any time, more or fewer securities than noted in this range.

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of companies that have market capitalizations in the range of the companies in the Russell Midcap® Value Index (the Capitalization Index), which ranged between $81.5 million and $251 billion as of May 31, 2026, that the Fund’s investment manager believes are undervalued and have the potential for long-term growth. The market capitalization range and composition of companies in the Capitalization Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund may continue to hold a security even if the company’s market capitalization is no longer within the range of the Capitalization Index. Under normal circumstances, the Fund also invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of “value” companies. The Fund considers “value” companies to be those companies that are either constituents of an index constructed by a third party to identify companies with various characteristics of value companies, or that have a higher book-to-price (B/P) ratio than the median ranked stock within the company’s GICS sector, have a higher EBITDA/EV (earnings before interest, taxes, depreciation and amortization-to-enterprise value) or have a lower price-to-earnings ratio than the median ranked stock within the company’s GICS sector. The third-party broad-based index currently used to identify value companies is the Russell 3000® Value Index, although the Fund may change the referenced index without prior notice.

The Fund may invest up to 20% of its total assets in foreign securities. The Fund normally invests in common stocks and also may invest in real estate investment trusts. The Fund may at times emphasize one or more sectors in selecting its investments, including the financials and industrials sectors. The Fund may hold a small number of securities, consistent with its value investment approach. Generally, the Fund anticipates holding between 30 and 50 securities in its portfolio; however, the Fund may hold, at any time, more or fewer securities than noted in this range.