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Metropolitan West Floating Rate Income Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Metropolitan West Floating Rate Income Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The Floating Rate Income Fund (the “Fund”) seeks primarily to maximize current income,
Objective, Secondary [Text Block] rr_ObjectiveSecondaryTextBlock with a secondary objective of long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
The table below describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (Fees paid directly from your investment)
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 July 31, 2023
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover 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 49% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 49.00%
Expense Footnotes [Text Block] rr_ExpenseFootnotesTextBlock
1 
The Fund is authorized to compensate broker-dealers and other third-party intermediaries up to 0.10% (10 basis points) of the M and I Class assets serviced by those intermediaries for shareholder services.
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 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 cost for the Fund reflects the net expenses of the Fund that result from the contractual expense limitation in the first year only (through July 31, 2023). The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund pursues its objective by investing, under normal circumstances, at least 80% of its net assets, plus any borrowings for investment purposes, in floating rate investments and in investments that are the economic equivalent of floating rate investments. These economically equivalent investments may include, but are not limited to, any combination of the following items: (i) senior secured floating rate loans or debt; (ii) second lien or other subordinated or 
unsecured floating rate loans or debt; (iii) fixed-rate loans or debt, such as corporate bonds, preferred securities, convertible securities, mezzanine investments, collateralized loan obligations, senior loans, second lien loans, structured products and U.S. government debt securities, with respect to which the Fund has entered into derivative instruments that have the effect of converting the fixed-rate interest payments into floating-rate interest payments; and (iv) written credit derivatives, which would give the Fund exposure to the credit of a single issuer or an index. The market value of written credit derivatives would count toward the 80% test specified above. The Fund may also purchase, without limitation, participations or assignments in senior floating rate loans or second lien floating rate loans. Debt instruments include convertible or preferred securities that produce income. 
The portfolio managers may consider many factors in purchasing and selling investments for the Fund, such as a fundamental analysis of the issuer, the credit quality of the issuer and collateral for the investment, capital structure, leverage, operating results for the issuer and the business outlook for the issuer, industry or broader economy. 
The Fund’s investments may have any credit quality without limitation, including investments rated below investment grade (commonly known as “junk bonds”). Under normal circumstances, a substantial portion of the Fund’s portfolio consists of leveraged loans rated below investment grade or unrated. 
The Fund may invest up to 20% of its net assets, plus any borrowings for investment purposes, in fixed income securities with respect to which the Fund has not entered into derivative instruments to effectively convert the fixed-rate interest payments into floating-rate interest payments. Those fixed income securities may include, but are not limited to, corporate bonds, preferred securities, convertible securities, mezzanine investments, collateralized loan obligations, senior loans, second lien loans, structured products and U.S. government debt securities. 
The Fund’s portfolio securities may have any duration or maturity. 
The Fund may invest in securities of foreign issuers, including issuers located in emerging markets. Under normal circumstances, the Fund invests at least 80% of its net assets in loans and other securities of U.S. issuers or issuers with their primary operations, assets or management activities in the U.S. (including limited purpose controlled affiliates outside of the U.S. that borrow or issue securities primarily for the bene- 
fit of their U.S. parent companies or affiliates). The Fund may invest up to 20% of its assets in securities of foreign issuers. Investments in securities of foreign issuers that are not denominated in U.S. dollars are limited to a maximum of 20% of the Fund’s assets. The Fund may invest up to 20% of its assets in emerging market securities. 
Up to 15% of the Fund’s net assets may be invested in illiquid securities. 
The Fund may also invest in companies whose financial condition is uncertain, where the borrower has defaulted in the payment of interest or principal or in the performance of its covenants or agreements, or that may be involved in bankruptcy proceedings, reorganizations or financial restructurings. 
The Fund may invest up to 10% of its net assets in common stocks or other equity securities. In addition, the Fund may acquire and hold those securities (or rights to acquire such securities) in unit offerings with fixed income securities, in connection with an amendment, waiver, conversion or exchange of fixed income securities, in connection with the bankruptcy or workout of a distressed fixed income security, or upon the exercise of a right or warrant obtained on account of a fixed income security. 
The Fund may use derivatives for hedging purposes, but is not required to do so, as well as to increase the total return on its portfolio investments. The types of derivative instruments in which the Fund will principally invest are options or futures on a security or an index of securities, options on futures, credit default swaps, and interest rate or foreign currency derivatives, including swaps and forward contracts. 
The Fund may sell securities and other instruments short provided that not more than 15% of its net assets are held as collateral for those transactions. 
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
Because the Fund holds securities with fluctuating market prices, the value of the Fund’s shares will vary as its portfolio holdings increase or decrease in value. Therefore, the value of your investment in the Fund could go down as well as up. You can lose money by investing in the Fund.
The principal risks affecting the Fund that can cause a decline in value are:
  
•  
Debt Securities Risk: the risk that the value of a debt security may increase or decrease as a result of various factors, 
   
including changes in interest rates, actual or perceived inability or unwillingness of issuers to make principal or interest payments, market fluctuations and illiquidity in the debt securities market. 
•   Market Risk: the risk that returns from the investments held by the Fund may underperform returns from the general securities markets or other types of securities. 
•   Credit Risk: the risk that an issuer may default in the payment of principal and/or interest on a security. 
•   Inflation Risk: the risk that the value of the Fund’s investments may not keep up with price increases from inflation. 
•   Issuer Risk: the risk that the value of a security may decline for reasons directly related to the issuer such as management performance, financial leverage and reduced demand for the issuer’s goods or services. 
•   Liquidity Risk: the risk that lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price. In addition, the Fund, by itself or together with other accounts managed by the Adviser, may hold a position in a security that is large relative to the typical trading volume for that security, which can make it difficult for the Fund to dispose of the position at an advantageous time or price. Although the Fund is normally able to sell loans within seven days, a substantial portion of the loans held by the Fund may also experience delayed settlement beyond that period, which can impair the ability of the Fund to pay redemptions or to re-invest proceeds, or may require the Fund to borrow to meet redemptions. Over recent years, the fixed-income markets have grown more than the ability of dealers to make markets, which can further constrain liquidity and increase the volatility of portfolio valuations. High levels of redemptions in bond funds in response to market conditions could cause greater losses as a result. Regulations such as the Volcker Rule or future regulations may further constrain the ability of market participants to create liquidity, particularly in times of increased market volatility. The liquidity of the Fund’s assets may change over time. 
•   Valuation Risk: the risk that the portfolio instruments may be sold at prices different from the values established by the Fund, particularly for investments that trade in low volume, in volatile markets or over the counter or that are fair valued. 
•   Bank Loan Risk: the risk of investing in corporate loans made by commercial banks and other financial institutions or institutional investors to companies that need capital to grow or restructure, which includes interest rate risk, liquidity risk and prepayment risk. The Fund may also be 
   
subject to the credit risk of other financial institutions and the risks associated with insufficient collateral securing a bank loan, limited available public information about a bank loan, delayed settlement, and less protection for holders of bank loans as compared to holders of registered securities. 
•   Senior Loan Risk: the risk of investing in senior loans, which may be greater than the risk of investing in other types of securities, as a result of, among other factors, less readily available, reliable information about most senior loans than is the case for many other types of securities; possible loss of significant value before a default occurs; possible decline in value or illiquidity of collateral; and lack of an active trading market for certain senior loans. 
•   Second Lien Loan Risk: the risk of investing in second lien loans, which generally are subject to similar risks as those associated with investments in senior loans as well as the additional risk that the cash flow of the borrower and property securing the loan or debt, if any, may be insufficient to meet scheduled payments after giving effect to the senior secured obligations of the borrower. 
•   Mezzanine Securities Risk: the risk of investing in mezzanine securities, which generally are rated below investment grade or are unrated and present many of the same risks as senior loans, second lien loans and non-investment grade bonds. Mezzanine securities present additional risks because they typically are the most subordinated debt obligation in an issuer’s capital structure and are often unsecured. Mezzanine securities are also expected to be a highly illiquid investment. 
•   Junk Bond Risk: the risk that junk bonds have a higher degree of default risk and may be less liquid and subject to greater price volatility than investment grade bonds. 
•   Unrated Securities Risk: the risk that unrated securities may be less liquid than comparable rated securities, and the risk that the Adviser may not accurately evaluate the security’s comparative credit rating. 
•   Distressed and Defaulted Securities Risk: the risk that the repayment of defaulted securities and obligations of distressed issuers is subject to significant uncertainties. 
•   Prepayment Risk: the risk that in times of declining interest rates, the Fund’s higher yielding securities may be prepaid and the Fund may have to replace them with securities having a lower yield. 
•  
Securities Selection Risk: the risk that the securities held by the Fund may underperform those held by other funds investing in the same asset class or those included in 
   
benchmarks that are representative of the same asset class because of the portfolio managers’ choice of securities. 
•   Price Volatility Risk: the risk that the value of the Fund’s investment portfolio will change as the prices of its investments go up or down. 
•   Interest Rate Risk: the risk that investments held by the Fund may decline in value because of changes in interest rates. 
•   Derivatives Risk: the risk of investing in derivative instruments, which includes liquidity, interest rate, market, credit and management risks as well as risks related to mispricing or improper valuation. Changes in the value of a derivative may not correlate perfectly with the underlying asset, reference rate or index, and the Fund could lose more than the principal amount invested. These investments can create investment leverage and may create additional risks that may subject the Fund to greater volatility and less liquidity than investments in more traditional securities. 
•   Swap Agreements Risk: the risk of investing in swaps, which, in addition to risks applicable to derivatives generally, includes: (1) the inability to assign a swap contract without the consent of the counterparty; (2) potential default of the counterparty to a swap for those not traded through a central counterparty; (3) absence of a liquid secondary market for any particular swap at any time; and (4) possible inability of the Fund to close out a swap transaction at a time that otherwise would be favorable for it to do so. 
•   Futures Contracts Risk: the risk of investing in futures contracts, which includes (1) the imperfect correlation between a futures contract and the change in market value of the underlying instrument held by the Fund; (2) a high degree of leverage because of the low collateral deposits normally involved in futures trading; (3) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (4) losses caused by unanticipated market movements, which are potentially unlimited; and (5) the inability of the Fund to execute a trade because of the maximum permissible price movements exchanges may impose on futures contracts. 
•   Counterparty Risk: the risk that the other party to a contract, such as a derivatives contract, may not fulfill its contractual obligations. 
•   Foreign Investing Risk: the risk that Fund share prices will fluctuate with market conditions, currency exchange rates and the economic and political climates of the foreign countries in which the Fund invests or has exposure. Investments in foreign securities may involve greater risks 
   
than investing in U.S. securities due to, among other factors, less publicly available information, less stringent and less uniform accounting, auditing and financial reporting standards, less liquid and more volatile markets, higher transaction and custody costs, additional taxes, less investor protection, delayed or less frequent settlement, political or social instability, civil unrest, acts of terrorism, regional economic volatility, and the imposition of sanctions, confiscations, trade restrictions (including tariffs) and other government restrictions by the United States and/or other governments. In addition, Russia’s recent military incursions in Ukraine have led to, and may lead to additional, sanctions being levied by the United States, European Union and other countries against Russia. Russia’s military incursion and the resulting sanctions could adversely affect global energy and financial markets and thus could affect the value of the Fund’s investments. 
•   Emerging Markets Risk: the risk of investing in emerging market countries, which is substantial due to, among other factors, higher brokerage costs in certain countries; different accounting standards; thinner trading markets as compared to those in developed countries; less publicly available and reliable information about issuers as compared to developed markets; the possibility of currency transfer restrictions; and the risk of expropriation, nationalization or other adverse political, economic or social developments. 
•   Equity Risk: the risk that stocks and other equity securities generally fluctuate in value more than bonds and may decline in value over short or extended periods as a result of changes in a company’s financial condition or in overall market, economic and political conditions. 
•   Leverage Risk: the risk that leverage may result from certain transactions, including the use of derivatives and borrowing. This may impair the Fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase its volatility or otherwise cause it not to achieve its intended result. To the extent required by applicable law or regulation, the Fund will reduce leverage risk either by segregating an equal amount of liquid assets or by “covering” the transactions that introduce such risk. 
•   Portfolio Management Risk: the risk that an investment strategy may fail to produce the intended results. 
•  
Public Health Emergency Risk: the risk that pandemics and other public health emergencies, including outbreaks of infectious diseases such as the current outbreak of the novel coronavirus (“COVID-19”), can result, and in the case of COVID-19 has resulted and may continue to result, in market volatility and disruption, and materially and 
   
adversely impact economic conditions in ways that cannot be predicted, all of which could result in substantial investment losses. The ultimate impact of COVID-19, including new variants of the underlying virus, or other health emergencies on global economic conditions and businesses is impossible to predict accurately. Ongoing and potential additional material adverse economic effects of indeterminate duration and severity are possible. The resulting adverse impact on the value of an investment in the Fund could be significant and prolonged. Other public health emergencies that may arise in the future could have similar or other unforeseen effects. 
•   LIBOR Risk: the risk associated with the transition away from LIBOR, which is used extensively in the U.S. and globally as a “benchmark” or “reference rate” for various commercial and financial contracts, including corporate bonds and other fixed income securities. The use of LIBOR began being phased out at the end of 2021; however, the publication of 1-month, 3-month and 6-month USD LIBOR has been extended until June 2023. Although the transition process away from LIBOR has become increasingly well-defined, there remains uncertainty regarding the impact on the Fund of the transition to a new reference rate. 
•   U.S. Government Securities Risk: the risk that debt securities issued or guaranteed by certain U.S. government agencies, instrumentalities, and sponsored enterprises are not supported by the full faith and credit of the U.S. government, and as a result investments in securities or obligations issued by such entities involve credit risk greater than investments in other types of U.S. government securities. 
Please see “Principal Risks” and “Other Risks” for a more detailed description of the risks of investing in the Fund. 
Your investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, entity, or person.
Risk Lose Money [Text] rr_RiskLoseMoney You can lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution Your investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, entity, or person.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year. The bar chart shows performance of the Fund’s Class M shares. Class M performance is lower than Class I and Plan Class performance because Class I and Plan Class have lower expenses than Class M. The table compares the average annual total returns of the Fund to a broad-based securities 
market index. Total returns would have been lower if certain fees and expenses had not been waived or reimbursed. The inception date of Class M shares and Class I shares of the Fund is June 28, 2013. The inception date for the Plan Class shares is January 29, 2021. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information for the Fund is available on our website at www.tcw.com or by calling (800) 241-4671. 
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year. The bar chart shows performance of the Fund’s Class M shares. Class M performance is lower than Class I and Plan Class performance because Class I and Plan Class have lower expenses than Class M. The table compares the average annual total returns of the Fund to a broad-based securities market index.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone (800) 241-4671
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.tcw.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Floating Rate Income Fund – Class M Shares Annual Total Returns for Years Ended 12/31
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Year-to-Date Total Return of Class M Shares as of June 30, 2022: -5.38% 
Highest:        6.99%    (quarter ended June 30, 2020)
Lowest:        -8.90%    (quarter ended March 31, 2020)
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns(For Periods Ended December 31, 2021)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual 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 shown 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 only Class M Shares. After-tax returns for other classes will vary.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher In some cases, returns after taxes on distributions and sale of Fund sharesmay be higher than returns before taxes because the calculations assume that the investor received a tax deduction for any loss incurred on the sale of the shares.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock
After-tax returns are calculated using the historical highest individual 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 tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only Class M Shares. After-tax returns for other classes will vary. In some cases, returns after taxes on distributions and sale of Fund shares
may be higher than returns before taxes because the calculations assume that the investor received a tax deduction for any loss incurred on the sale of the shares.
Metropolitan West Floating Rate Income Fund | M Class  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees (Fees paid directly from your investment) rr_ShareholderFeeOther none
Management Fees rr_ManagementFeesOverAssets 0.55%
Distribution (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Shareholder Servicing Expenses rr_Component1OtherExpensesOverAssets 0.10% [1]
Other Expenses rr_OtherExpensesOverAssets 0.20%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.00%
Fee Waiver and/or Expense Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.10%)
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.90%
1 Year rr_ExpenseExampleYear01 $ 92
3 Years rr_ExpenseExampleYear03 308
5 Years rr_ExpenseExampleYear05 543
10 Years rr_ExpenseExampleYear10 $ 1,216
2014 rr_AnnualReturn2014 2.01%
2015 rr_AnnualReturn2015 1.36%
2016 rr_AnnualReturn2016 6.04%
2017 rr_AnnualReturn2017 3.29%
2018 rr_AnnualReturn2018 0.40%
2019 rr_AnnualReturn2019 7.28%
2020 rr_AnnualReturn2020 2.99%
2021 rr_AnnualReturn2021 3.30%
Year to Date Return, Label rr_YearToDateReturnLabel Year-to-Date Total Return of Class M Shares as of June 30, 2022:
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Jun. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (5.38%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 6.99%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (8.90%)
1 Year rr_AverageAnnualReturnYear01 3.30%
5 Years rr_AverageAnnualReturnYear05 3.43%
Since Inception rr_AverageAnnualReturnSinceInception 3.57%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 28, 2013
Metropolitan West Floating Rate Income Fund | I Class  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees (Fees paid directly from your investment) rr_ShareholderFeeOther none
Management Fees rr_ManagementFeesOverAssets 0.55%
Distribution (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Shareholder Servicing Expenses rr_Component1OtherExpensesOverAssets 0.04% [1]
Other Expenses rr_OtherExpensesOverAssets 0.14%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.69%
Fee Waiver and/or Expense Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.69%
1 Year rr_ExpenseExampleYear01 $ 70
3 Years rr_ExpenseExampleYear03 221
5 Years rr_ExpenseExampleYear05 384
10 Years rr_ExpenseExampleYear10 $ 859
1 Year rr_AverageAnnualReturnYear01 3.51%
5 Years rr_AverageAnnualReturnYear05 3.66%
Since Inception rr_AverageAnnualReturnSinceInception 3.78%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 28, 2013
Metropolitan West Floating Rate Income Fund | Plan Class  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees (Fees paid directly from your investment) rr_ShareholderFeeOther none
Management Fees rr_ManagementFeesOverAssets 0.55%
Distribution (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Shareholder Servicing Expenses rr_Component1OtherExpensesOverAssets none [1]
Other Expenses rr_OtherExpensesOverAssets 0.10%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.65%
Fee Waiver and/or Expense Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.05%)
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.60%
1 Year rr_ExpenseExampleYear01 $ 61
3 Years rr_ExpenseExampleYear03 203
5 Years rr_ExpenseExampleYear05 357
10 Years rr_ExpenseExampleYear10 $ 806
1 Year rr_AverageAnnualReturnYear01
5 Years rr_AverageAnnualReturnYear05
Since Inception rr_AverageAnnualReturnSinceInception
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 29, 2021
Metropolitan West Floating Rate Income Fund | After Taxes on Distributions | M Class  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 2.07%
5 Years rr_AverageAnnualReturnYear05 1.88%
Since Inception rr_AverageAnnualReturnSinceInception 2.02%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 28, 2013
Metropolitan West Floating Rate Income Fund | After Taxes on Distributions and Sale of Fund Shares | M Class  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 1.94%
5 Years rr_AverageAnnualReturnYear05 1.94%
Since Inception rr_AverageAnnualReturnSinceInception 2.04%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 28, 2013
Metropolitan West Floating Rate Income Fund | S&P/LSTA Leveraged Loan Index  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 5.20%
5 Years rr_AverageAnnualReturnYear05 4.26%
Since Inception rr_AverageAnnualReturnSinceInception 4.11%
[1] Metropolitan West Asset Management, LLC (the “Adviser”) has contractually agreed to reduce advisory fees and/or reimburse expenses, including distribution expenses, to limit the Fund’s total annual operating expenses (excluding interest, taxes, brokerage commissions, short sale dividend expenses, swap interest expenses, acquired fund fees and expenses, and any expenses incurred in connection with any merger or reorganization or extraordinary expenses such as litigation), to 0.90% for M Class, 0.70% for I Class and 0.60% for Plan Class. The Adviser may recoup reduced fees and expenses only within three years of the waiver or reimbursement, provided that the recoupment does not cause the Fund’s annual expense ratio to exceed the lesser of (i) the expense limitation applicable at the time of that fee waiver and/or expense reimbursement or (ii) the expense limitation in effect at the time of recoupment. This contract will remain in place until July 31, 2023, and the Adviser may not terminate the contract before that date. Although it does not expect to do so, the Board of Trustees is permitted to terminate this contract sooner in its discretion with written notice to the Adviser.