S000000852 [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Parnassus Mid Cap Growth Fund | Investor Shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 9.19% | 10.55% | 35.60% | (33.52%) | 9.37% | 28.61% | 29.82% | (9.73%) | 16.08% | 13.46% |