The Fund aims to achieve its objective by approximating the total return of the CRSP Cap-Based Portfolio 10 Index (the “Index”) published by the Center for Research in Security Prices, LLC (“CRSP”), an affiliate of the University of Chicago over longer time periods. Under normal circumstances, the Fund invests at least 80% of its net assets (plus borrowings for investment purposes) in ultra-small company stocks based on company size at the time of purchase. For purposes of the Fund’s investments, “ultra-small companies” are defined as those: (i) companies that have a market capitalization the size of the smallest 10% of companies listed on the New York Stock Exchange; or (ii) companies with a capitalization that falls within the range of capitalization of companies included in the Index as defined by CRSP. A majority of the stocks in the Fund are listed on Nasdaq. On June 30, 2025, the stocks in this group generally had a market capitalization of less than $329 million. Bridgeway Capital Management, LLC (the “Adviser”) invests in a representative sample of the companies included in the Index using a statistical approach. However, the Adviser also may invest in companies that are not included in the Index.

The Adviser’s investment process incorporates material environmental, social, and governance (“ESG”) information, when available, as a consideration in the ongoing assessment of potential portfolio securities. The Adviser uses ESG research and/or ratings information provided by third parties in performing this analysis and considering ESG risks. As with any consideration used in assessing portfolio securities, the Adviser may, at times, utilize ESG information to increase the weighting of an issuer with a good ESG record or decrease the weighting of an issuer with a poor ESG record. However, as ESG information is just one investment consideration, ESG considerations are not solely determinative in any investment decision made by the Adviser. ESG information for ultra-small companies may be limited, although the Adviser’s investment process incorporates this information when available.

The Adviser also seeks to minimize the distribution of capital gains, within the constraints of the investment objective and ultra-small company focus, by offsetting capital gains with capital losses. By paying close attention to trading, the Adviser seeks to conduct such tax management without detriment to the overall Fund return.

S000004424 [Member] Investment Strategy - Ultra-Small Company Market Fund	Jun. 30, 2025
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies:
Strategy Narrative [Text Block]	The Fund aims to achieve its objective by approximating the total return of the CRSP Cap-Based Portfolio 10 Index (the “Index”) published by the Center for Research in Security Prices, LLC (“CRSP”), an affiliate of the University of Chicago over longer time periods. Under normal circumstances, the Fund invests at least 80% of its net assets (plus borrowings for investment purposes) in ultra-small company stocks based on company size at the time of purchase. For purposes of the Fund’s investments, “ultra-small companies” are defined as those: (i) companies that have a market capitalization the size of the smallest 10% of companies listed on the New York Stock Exchange; or (ii) companies with a capitalization that falls within the range of capitalization of companies included in the Index as defined by CRSP. A majority of the stocks in the Fund are listed on Nasdaq. On June 30, 2025, the stocks in this group generally had a market capitalization of less than $329 million. Bridgeway Capital Management, LLC (the “Adviser”) invests in a representative sample of the companies included in the Index using a statistical approach. However, the Adviser also may invest in companies that are not included in the Index. The Adviser’s investment process incorporates material environmental, social, and governance (“ESG”) information, when available, as a consideration in the ongoing assessment of potential portfolio securities. The Adviser uses ESG research and/or ratings information provided by third parties in performing this analysis and considering ESG risks. As with any consideration used in assessing portfolio securities, the Adviser may, at times, utilize ESG information to increase the weighting of an issuer with a good ESG record or decrease the weighting of an issuer with a poor ESG record. However, as ESG information is just one investment consideration, ESG considerations are not solely determinative in any investment decision made by the Adviser. ESG information for ultra-small companies may be limited, although the Adviser’s investment process incorporates this information when available. Although the Fund seeks investments across a number of sectors, from time to time, based on portfolio positioning to reflect its benchmark, the Fund may have significant positions in particular sectors. The Adviser also seeks to minimize the distribution of capital gains, within the constraints of the investment objective and ultra-small company focus, by offsetting capital gains with capital losses. By paying close attention to trading, the Adviser seeks to conduct such tax management without detriment to the overall Fund return.