The Parnassus Value Equity Fund’s objective is to achieve capital appreciation by investing primarily in a diversified portfolio of equity securities. Equity securities include common and preferred stock. Under normal circumstances, the Fund will invest a minimum of 80% of its net assets (plus borrowings for investment purposes) in equity securities. These companies must, in the Adviser’s opinion, be undervalued, but they must also have good prospects for long-term capital appreciation over the course of the expected holding period. The Parnassus Value Equity Fund is primarily a large‑cap fund, which means that it normally invests more than half of its net assets in large, well-established companies. The Fund may invest to a lesser extent in small- and mid‑capitalization companies. The Fund may purchase foreign securities directly on foreign markets. The Fund invests mainly in domestic stocks of companies that are financially sound and have good prospects for the future, and to a lesser extent may also invest in foreign securities of

similar companies. To determine a company’s prospects, the Fund’s investment adviser, Parnassus Investments, LLC (the “Adviser”), reviews the company’s income statement, cash flow statement and balance sheet, and analyzes the company’s sustainable strategic advantage and management team. Upon initial investment, a company’s stock must be deemed to represent relative value. To determine whether the company demonstrates relative value, the Adviser considers the company’s valuation relative to its own valuation history and relative to similar companies operating in the same industry. As part of the Adviser’s investment approach, the Adviser seeks to invest in companies with sustainable business practices, in alignment with our investment philosophy, as we believe these factors are relevant to our assessment of quality and the risk-return profiles of companies in the Funds. The Fund will evaluate whether it will continue to hold or sell a security if the Adviser believes a company’s fundamentals will deteriorate, if it believes a company’s stock has little potential for appreciation or if the company no longer meets the Adviser’s sustainable investment expectations and the Adviser does not believe it is an appropriate investment for the Fund following such changes.

S000000855 [Member] Investment Strategy - Parnassus Value Equity Fund	Dec. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	The Parnassus Value Equity Fund’s objective is to achieve capital appreciation by investing primarily in a diversified portfolio of equity securities. Equity securities include common and preferred stock. Under normal circumstances, the Fund will invest a minimum of 80% of its net assets (plus borrowings for investment purposes) in equity securities. These companies must, in the Adviser’s opinion, be undervalued, but they must also have good prospects for long-term capital appreciation over the course of the expected holding period. The Parnassus Value Equity Fund is primarily a large‑cap fund, which means that it normally invests more than half of its net assets in large, well-established companies. The Fund may invest to a lesser extent in small- and mid‑capitalization companies. The Fund may purchase foreign securities directly on foreign markets. The Fund invests mainly in domestic stocks of companies that are financially sound and have good prospects for the future, and to a lesser extent may also invest in foreign securities of similar companies. To determine a company’s prospects, the Fund’s investment adviser, Parnassus Investments, LLC (the “Adviser”), reviews the company’s income statement, cash flow statement and balance sheet, and analyzes the company’s sustainable strategic advantage and management team. Upon initial investment, a company’s stock must be deemed to represent relative value. To determine whether the company demonstrates relative value, the Adviser considers the company’s valuation relative to its own valuation history and relative to similar companies operating in the same industry. As part of the Adviser’s investment approach, the Adviser seeks to invest in companies with sustainable business practices, in alignment with our investment philosophy, as we believe these factors are relevant to our assessment of quality and the risk-return profiles of companies in the Funds. The Fund will evaluate whether it will continue to hold or sell a security if the Adviser believes a company’s fundamentals will deteriorate, if it believes a company’s stock has little potential for appreciation or if the company no longer meets the Adviser’s sustainable investment expectations and the Adviser does not believe it is an appropriate investment for the Fund following such changes.