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PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Parnassus Fixed Income Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Parnassus Fixed Income Fund’s objective is a high level of current income consistent with safety and preservation of capital.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Parnassus Fixed Income Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and example below.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (%) (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination May 1, 2024
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
The Parnassus Fixed Income Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 58.7% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 58.70%
Expense Footnotes [Text Block] rr_ExpenseFootnotesTextBlock
For additional information about the Parnassus Fixed Income Fund’s expenses, please see “Financial Highlights” in the prospectus.
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This example is intended to help you compare the cost of investing in the Parnassus Fixed Income Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example
also assumes that your investment has a 5% return each year, and that the Fund’s expenses are equal to the total annual fund operating expenses after expense waiver and reimbursement for the first year and the total annual fund operating expenses for the remaining years. Although your actual costs may be higher or lower, under these assumptions, your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Parnassus Fixed Income Fund normally invests at least 80% of its net assets (plus borrowings for investment purposes) in a diversified portfolio of bonds and other fixed income instruments. The Fund principally invests in corporate bonds, U.S. Treasuries and supranational bonds, with an emphasis on corporate bonds. Other investments may include convertible bonds, preferred stock, and fixed income exchange traded funds, and the Fund may buy and sell futures contracts based on fixed income securities and interest rates to seek to enhance returns, manage duration, hedge interest rate risk, and reduce volatility. The Fund may also invest in U.S. governmental agencies, commercial and residential mortgage-backed securities and other asset-backed securities. The Fund invests mainly in domestic securities, and to a lesser extent may also invest in U.S. dollar-denominated foreign securities. The Fund may purchase foreign
securities directly on foreign markets. The Fund applies a fossil-fuel free investment strategy, meaning that it does not invest in companies that derive significant revenues from the extraction, exploration, production or refining of fossil fuels. Pursuant to the strategy, the Fund may invest in companies that use fossil fuel-based energy to power their operations or for other purposes. The Fund defines “significant revenues” as being 10% or greater. The Fund normally invests at least 80% of its net assets in fixed income securities that have investment-grade ratings (namely rated at least BBB-by Standard & Poor’s Rating Group [“S&P”] or at least Baa3 by Moody’s Investors Services, Inc. [“Moody’s”]) or, if unrated, have been determined by the Fund’s investment adviser, Parnassus Investments, LLC (the “Adviser”) to be of similar economic quality. At any given time, up to 20% of the portfolio may be invested in non-investment grade fixed income securities (otherwise known as “high-yield” or “junk bonds”) or unrated fixed income securities determined by the Adviser to be of similar economic quality. Non-investment grade and unrated securities are more risky than investment-grade securities. The Fund may also invest in preferred stocks. The Fund’s Adviser also takes environmental, social and governance (“ESG”) factors into account when making investment decisions, as discussed in more detail in the prospectus. The Fund may sell a security if the Adviser believes it no longer meets the Fund’s investment objective or if the issuer no longer meets the Adviser’s ESG expectations. The Fund may invest in long-term, intermediate-term or short-term fixed income securities or any combination thereof, depending on market conditions, and these securities may also have floating or variable interest rates. As of March 31, 2023, the dollar-weighted average maturity of the Fund’s portfolio was 9.63 years.
Risk [Heading] rr_RiskHeading Principal Risks
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The bar chart and table that follow contain information that allows you to evaluate the Parnassus Fixed Income Fund’s performance using several measures, such as yearly changes in performance, best and worst quarterly returns, and average annual total returns before and after taxes compared to a broad measure of market performance. The bar chart shows the performance of the Fund’s Investor Shares, and the performance of the Fund’s Institutional Shares will differ from those shown to the extent that the classes of shares do not have the same expenses or inception date. How the Fund performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Updated performance information is available on the Fund’s website, www.parnassus.com, or by calling toll-free at (800) 999-3505.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table that follow contain information that allows you to evaluate the Parnassus Fixed Income Fund’s performance using several measures, such as yearly changes in performance, best and worst quarterly returns, and average annual total returns before and after taxes compared to a broad measure of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone (800) 999-3505
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.parnassus.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture How the Fund performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Annual Total Returns (%)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
During the ten-year period shown in the bar chart, the highest return for a quarter was 4.2% (quarter ended March 31, 2019), and the lowest return for a quarter was a loss of 6.7% (quarter ended March 31, 2022).
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns (%) (all periods ended December 31, 2022)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns are calculated using the historical highest individual stated federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Investor Shares only. After-tax returns for Institutional Shares will vary.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of Fund shares.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock
Following is a table comparing the performance of the Parnassus Fixed Income Fund’s two share classes with that of the Bloomberg U.S. Aggregate Bond Index (formerly known as the Bloomberg Barclays U.S. Aggregate Bond Index) (see “Index Descriptions” in the prospectus). Figures are average annual returns for the one-, five- and ten-year periods ended December 31, 2022. The table is intended to demonstrate the risk of investing in the Fund by showing how the Fund’s average annual total returns, before and after taxes, compare with a broad measure of market performance, the Bloomberg U.S. Aggregate Bond Index, and a group of similar mutual funds, and also how the Fund’s performance varies from year to year.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
The after-tax returns are calculated using the historical highest individual stated federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s individual tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of Fund shares. After-tax returns are shown for Investor Shares only. After-tax returns for Institutional Shares will vary.
Parnassus Fixed Income Fund—Institutional Shares were incepted on April 30, 2015. Performance shown prior to the inception of the Institutional Shares reflects the performance of the Parnassus Fixed Income Fund—Investor Shares and includes expenses that are not applicable to and are higher than those of the Institutional Shares.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Risk Lose Money [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock You could lose money investing in the Fund.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Risk Not Insured Depository Institution [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Investments in the Fund are not deposits, endorsements or guarantees of any bank and are not insured by the Federal Deposit Insurance Corporation or any other government agency.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Interest Rate Risks [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Interest Rate Risk. In general, bond prices are inversely related to interest rates. As interest rates
 
drop, bond prices will likely go up, and as interest rates go up, the value of bonds will likely go down. A rising interest rate environment may cause investors to move out of bonds and other debt securities on a large scale, which could adversely affect the price and liquidity of such securities. Recent inflationary price movements may cause bonds and other debt securities and related markets to experience heightened levels of interest rate volatility and liquidity risk.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Credit Risks [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Credit Risk. There is a possibility that issuers of debt obligations will not pay the Fund interest or principal or that their credit rating may be downgraded by a ratings agency. During time periods characterized by recessionary market pressures such as inflationary price movements, rising interest rates, bank failures and other negative market stresses, credit risk increases.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Duration Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Duration Risk. Duration is a measure that relates the expected price volatility of a fixed-income instrument to changes in interest rates. The duration of a fixed-income security may be shorter than or equal to full maturity of the fixed-income security. Fixed-income securities with longer durations have more risk and will decrease in price as interest rates rise. For example, a fixed-income security with a duration of three years would be expected to decrease in value by approximately 3% if interest rates increase by 1%.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Market Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Market Risk. A security’s value may also be affected by market activity or by supply and demand. In the past decade, financial markets throughout the world have experienced increased volatility, decreased liquidity and heightened uncertainty. Risks associated with rising inflation, trade tensions, the war between Russia and Ukraine, the United Kingdom’s departure from the European Union (“Brexit”), and the impact of epidemic and pandemic diseases, such as COVID-19. Additionally, risks associated with volatility and disruptions in the banking sector (including bank failures), interest rate increases, political events, rising government debt in the U.S. and the possibility of a national or global recession could affect the economies of many nations, including the United States, in ways that cannot be foreseen at the present time, and may adversely impact the markets in which the Fund invests. If the Fund is unable to find buyers for a given security, this can have a negative effect on the Fund’s net asset value.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Non Investment Grade Risk and Unrated Bond Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Non-Investment Grade Risk and Unrated Bond Risk. Non-investment grade bonds (otherwise known as “high-yield” or “junk bonds”) and bonds that have not been rated by a nationally recognized statistical rating organization carry additional credit risk and are considered to be less safe than investment-grade bonds.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Mortgage Backed Securities Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Mortgage-Backed Securities Risk. Mortgage-backed securities are defined as obligations with pools of mortgages providing collateral, interest income and principal repayment. Such securities can be originated by private institutions or government-sponsored enterprises, like Fannie Mae and Freddie Mac, and the underlying mortgages can be either commercial or residential. Mortgage-backed securities, like all fixed income investments, have interest rate and credit risk. However, these securities also have extension and prepayment risk. Extension risk is the risk that a rise in interest rates or lack of refinancing opportunities can cause the Fund’s average maturity to lengthen unexpectedly due to a drop in expected prepayments of mortgage-backed securities. This would increase the Fund’s sensitivity to rising rates and its potential for price declines. Prepayment risk is the risk that the borrower will prepay some or all of the principal owed to the issuer. If prepayment occurs, the Fund may have to replace the security by investing the proceeds in a less attractive security. Prepayment may reduce the Fund’s share price and income distribution.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Exchange Traded Fund ETF Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Exchange Traded Fund (ETF) Risk. ETFs are investment companies that trade like stocks. The price of an ETF is derived from and based upon the securities held by the ETF. However, like stocks, shares of ETFs are not traded at net asset value, but may trade at prices above or below the value of their underlying portfolios. The level of risk involved in the purchase or sale of an ETF is similar to the risk involved in the purchase or sale of a traditional common stock, except that the pricing mechanism for an ETF is based on a basket of securities. Thus, the risks of owning an ETF generally reflect the risks of owning the underlying securities they are designed to track, although lack of liquidity in an ETF could result in it being more volatile than the underlying portfolio of securities. Disruptions in the markets for the securities underlying ETFs purchased or sold by a Fund could result in losses on a Fund’s investment in ETFs. ETFs are subject to management fees and other
   
fees that may increase their costs versus the costs of owning the underlying securities directly.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Convertible Securities Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Convertible Securities Risk. If market interest rates rise, the value of a convertible security usually falls. The issuer of a convertible security may not be able to pay interest or dividends when due, and their market value may change based on actual or perceived changes in the issuer’s creditworthiness. Convertible securities are also subject to the same types of risk that apply to the underlying security. The Fund may be forced to convert a convertible security at an inopportune time, which may decrease the Fund’s return and result in investment losses.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Preferred Stock Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Preferred Stock Risk. Preferred stocks may pay fixed or adjustable rates of return and are subject to many of the risks associated with debt securities (e.g., interest rate risk, call risk and extension risk). In addition, preferred stocks are subject to issuer-specific and market risks applicable generally to equity securities. Because many preferred stocks allow the issuer to convert their preferred stock into common stock, preferred stocks are often sensitive to declining common stock values. A company’s preferred stock generally pays dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred stocks will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Derivatives Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Derivatives Risk. The Fund’s use of futures based on fixed income instruments to enhance returns or hedge against market declines subjects the Fund to potentially greater volatility and/or losses. Even a small investment in futures can have a large impact on the Fund’s interest rate and securities market exposure. Therefore, using futures can disproportionately increase losses and reduce opportunities for gains when interest rates are changing. The Fund may not fully benefit from or may lose money on its investment in futures if changes in their value do not correspond accurately to changes in the value of the Fund’s holdings. The other party to certain futures presents the same types of credit risks as issuers of fixed income securities. Investing in futures can also make the Fund’s assets less liquid and harder to value, especially in declining markets.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Liquidity Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Liquidity Risk. Liquidity risk is the risk, due to certain investments trading in lower volumes or to market and economic conditions, that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects based on the Fund’s valuation of the investments. Events that may lead to increased redemptions, such as market disruptions, may also negatively impact the liquidity of the Fund’s investments when it needs to dispose of them. The potential for liquidity risk may be magnified by a rising interest rate environment or other circumstances where investor redemptions from fixed income mutual funds may be higher than normal, potentially causing increased supply in the market due to selling activity. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Liquidity issues may also make it difficult to value the Fund’s investments.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Information Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Information Risk. The risk that information about a security or issuer or the market might not be available, complete, accurate, or comparable.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Management Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Management Risk. The investment process used by the Adviser to select securities for the Fund’s investment portfolio may not prove effective, and the Adviser’s judgments about the attractiveness, value and potential appreciation of the Fund’s investments may prove to be incorrect in that the investments chosen by the Adviser may not perform as anticipated. Certain risks are inherent in the ownership of any security, and there is no assurance that the Fund’s investment objective will be achieved.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Environmental Social and Governance ESG Investing Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Environmental, Social, and Governance (ESG) Investing Risk. ESG investing risk is the risk stemming from the environmental, social, and governance factors that the Fund applies in selecting securities. The Fund intends to screen out companies that do not meet its ESG expectations. This may affect the Fund’s exposure to certain companies or industries and cause the Fund to forego certain investment opportunities. The Fund’s returns may be lower than other funds that do not seek to invest in companies based on ESG screens.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Fossil Fuel Free Investing Considerations Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Fossil-Fuel Free Investing Considerations Risk: Pursuing a fossil-fuel free investment strategy may
   
limit the number of investment opportunities available to the Fund, and as a result, at times, the Fund may underperform funds that are not subject to similar investment considerations. For example, the Fund may exclude fossil-fuel related investments when other considerations would suggest that investing in such securities would be advantageous. The Fund may also underperform funds that invest in the energy and utilities sectors, particularly in times of rising oil, gas and energy prices.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Foreign Securities Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Foreign Securities Risk. The Fund may invest up to 20% of its assets in foreign securities. Foreign markets can be more volatile and less liquid than the U.S. market due to increased risks of adverse issuer, political, regulatory, market or economic developments and can perform differently from the U.S. market. Policy and legislative changes in foreign countries and other events affecting global markets, such as international conflicts and wars, COVID-19 and Brexit, may contribute to decreased liquidity and increased volatility in the financial markets. Further, foreign companies may be subject to significantly higher levels of taxation than U.S. companies, including potentially confiscatory levels of taxation, thereby reducing the earnings potential of such foreign companies. Substantial withholding taxes may also apply to distributions from foreign companies.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Tax Law Change Risk [Member]  
Risk/Return: rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock
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Tax Law Change Risk: All statements contained in this prospectus regarding the U.S. federal income tax consequences of an investment in the Fund are based on current law, which is subject to change at any time, potentially with retroactive effect. For example, tax legislation enacted in 2017 (the Tax Cuts and Jobs Act) resulted in fundamental changes to the Internal Revenue Code (some of which are set to expire in the next few years). More recently, the Inflation Reduction Act of 2022 will add a 15% alternative minimum tax on large corporations and a 1% excise tax on repurchases of stock by publicly traded corporations and certain affiliates. The excise tax on repurchases of stock may cause some corporations in which the Fund invests to reduce liquidity opportunities for its investors, which could potentially reduce the value of your investment in the Fund. Such legislation, as well as possible future U.S. tax legislation and administrative guidance, could materially affect the tax consequences of your investment in the Fund and the Fund’s investments or holding structures.
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Investor Shares  
Risk/Return: rr_RiskReturnAbstract  
Management Fees rr_ManagementFeesOverAssets 0.48%
Distribution (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Service Fees rr_Component1OtherExpensesOverAssets 0.21%
All Remaining Other Expenses rr_Component2OtherExpensesOverAssets 0.13%
Other Expenses rr_OtherExpensesOverAssets 0.34%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.82%
Expense Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.24%
Total Annual Fund Operating Expenses After Expense Waiver and Reimbursement rr_NetExpensesOverAssets 0.58% [1]
1 Year rr_ExpenseExampleYear01 $ 59
3 Years rr_ExpenseExampleYear03 238
5 Years rr_ExpenseExampleYear05 431
10 Years rr_ExpenseExampleYear10 $ 991
2013 rr_AnnualReturn2013 (2.71%)
2014 rr_AnnualReturn2014 4.49%
2015 rr_AnnualReturn2015 0.70%
2016 rr_AnnualReturn2016 2.42%
2017 rr_AnnualReturn2017 3.10%
2018 rr_AnnualReturn2018 (1.12%)
2019 rr_AnnualReturn2019 9.63%
2020 rr_AnnualReturn2020 7.91%
2021 rr_AnnualReturn2021 (2.09%)
2022 rr_AnnualReturn2022 (14.29%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2019
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.20%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2022
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.70%)
One Year rr_AverageAnnualReturnYear01 (14.29%)
Five Years rr_AverageAnnualReturnYear05 (0.36%)
Ten Years rr_AverageAnnualReturnYear10 0.60%
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Institutional Shares  
Risk/Return: rr_RiskReturnAbstract  
Management Fees rr_ManagementFeesOverAssets 0.48%
Distribution (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Service Fees rr_Component1OtherExpensesOverAssets none
All Remaining Other Expenses rr_Component2OtherExpensesOverAssets 0.11%
Other Expenses rr_OtherExpensesOverAssets 0.11%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.59%
Expense Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.20%
Total Annual Fund Operating Expenses After Expense Waiver and Reimbursement rr_NetExpensesOverAssets 0.39% [1]
1 Year rr_ExpenseExampleYear01 $ 40
3 Years rr_ExpenseExampleYear03 169
5 Years rr_ExpenseExampleYear05 309
10 Years rr_ExpenseExampleYear10 $ 719
One Year rr_AverageAnnualReturnYear01 (14.10%)
Five Years rr_AverageAnnualReturnYear05 (0.15%)
Ten Years rr_AverageAnnualReturnYear10 0.76%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2015
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Return After Taxes on Distributions | Investor Shares  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (15.14%)
Five Years rr_AverageAnnualReturnYear05 (1.28%)
Ten Years rr_AverageAnnualReturnYear10 (0.31%)
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Return After Taxes on Distributions and Sale of Fund Shares | Investor Shares  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (8.43%)
Five Years rr_AverageAnnualReturnYear05 (0.59%)
Ten Years rr_AverageAnnualReturnYear10 0.18%
PARNASSUS INCOME FUNDS | Parnassus Fixed Income Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (13.01%)
Five Years rr_AverageAnnualReturnYear05 0.02%
Ten Years rr_AverageAnnualReturnYear10 1.06%
[1] The investment adviser has contractually agreed to waive 0.10% of its management fee for each class, and to reimburse the Fund for expenses to the extent necessary to limit total annual fund operating expenses to 0.58% of net assets for the Parnassus Fixed Income Fund—Investor Shares and to 0.39% of net assets for the Parnassus Fixed Income Fund—Institutional Shares. This agreement will not be terminated prior to May 1, 2024, and may be continued indefinitely by the investment adviser on a year-to-year basis.