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Label Element Value
Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName GMO TRUST
Prospectus Date rr_ProspectusDate Jun. 30, 2024
GMO Small Cap Quality Fund  
Risk Return Abstract rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading GMO SMALL CAP QUALITY FUND
Objective [Heading] rr_ObjectiveHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Investment objective</span>
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Total return.
Expense [Heading] rr_ExpenseHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Fees and expenses</span>
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The table below describes the fees and expenses that you may bear for each class of shares 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 table and example below.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Annual Fund operating expenses</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">(expenses that you bear each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination <span style="color:#000000;font-family:Times New Roman;font-size:8pt;font-style:italic;">June 30, 2025</span><span style="color:#000000;font-family:Times New Roman;font-size:8pt;font-style:italic;">June 30, 2025</span>
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Portfolio turnover</span>
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities. A higher portfolio turnover rate may result in higher transaction costs and, for holders of Fund shares subject to U.S. taxes, higher income taxes. These transaction costs, which are not reflected in Annual Fund operating expenses or in the Example, affect the Fund’s performance. During its fiscal year ended February 29, 2024, the Fund’s portfolio turnover rate (excluding short-term investments) was 61% of the average value of its portfolio securities. That portfolio turnover rate includes investments in U.S. Treasury Fund, which the Fund uses as a short-term investment vehicle for cash management. The Fund’s portfolio turnover rate during its fiscal year ended February 29, 2024, excluding transactions in U.S. Treasury Fund and other short-term investments, was 37% of the average value of its portfolio securities.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 61.00%
Expense Example [Heading] rr_ExpenseExampleHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Example</span>
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, regardless of whether or not you redeem your shares at the end of such periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same as those shown in the table. The one year amounts shown reflect the expense reimbursement and waiver noted in the expense table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Principal investment strategies</span>
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock GMO seeks to achieve the Fund’s investment objective by investing the Fund’s assets primarily in equities of U.S. small-cap companies that GMO believes to be of high quality. GMO believes a high quality company generally to be a company that has an established business that will deliver a high level of return on past investments and that will use cash flows to make investments with the potential for a high return on capital or to return cash to shareholders through dividends, share buybacks, or other mechanisms.In selecting securities for the Fund, GMO uses a combination of investment methods, typically considering both systematic factors, based on profitability, profit stability, leverage, and other publicly available financial information, and judgmental factors, based on GMO’s assessment of future profitability, capital allocation, growth opportunities, and sustainability against competitive forces. GMO also may rely on valuation methodologies, such as discounted cash flow analysis and multiples of price to earnings, revenues, book values or other fundamental metrics. The Fund also is permitted to invest directly and indirectly (e.g., through underlying funds or derivatives) in equities of companies tied economically to any country in the world, including emerging countries.At times, the Fund may have substantial exposure to a single asset class, industry, sector and companies with similar market capitalizations. The Fund may invest in securities of companies of any market capitalization. The factors GMO considers and investment methods GMO uses can change over time. GMO does not manage the Fund to, or control the Fund’s risk relative to, any securities index or securities benchmark.As an alternative to investing directly in equities, the Fund may invest in exchange-traded and over-the-counter (OTC) derivatives and exchange-traded funds (ETFs). The Fund also may invest in derivatives and ETFs in an attempt to obtain or adjust elements of its long or short investment exposure. Derivatives used may include futures, options, forward currency contracts, and swap contracts. In addition, the Fund may lend its portfolio securities.Under normal circumstances, the Fund invests directly and indirectly at least 80% of its assets in equities of small-cap companies (see “Name Policies”). The term “small-cap companies” means companies whose market capitalization at the time of investment is less than that of the companies in the bottom decile of market capitalization of the MSCI US IMI Index or that are included in the S&P 600 Index. As of May 31, 2024, the market capitalization of companies comprising the bottom decile of the MSCI US IMI Index by market capitalization ranged from approximately $20.7 million to $11.5 billion. As of May 31, 2024, the market capitalization for the companies comprising the S&P 600 Index ranged from approximately $119.1 million to $8.7 billion.The Fund also may invest in U.S. Treasury Fund, in money market funds unaffiliated with GMO, and directly in the types of investments typically held by money market funds.
Risk [Heading] rr_RiskHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Principal risks of investing in the Fund</span>
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Performance</span>
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s annual total returns from year to year for the periods indicated and by comparing the Fund’s average annual total returns for different calendar periods with those of a broad-based index. Share classes not shown would have substantially similar annual returns to those below because all share classes invest in the same portfolio of securities. Annual returns vary among share classes to the extent that they bear different expenses. Share classes that bear higher expenses than the share classes shown below would have lower returns. 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 your tax situation and may differ from those shown. After-tax returns shown are not relevant if you are tax-exempt or if you hold your Fund shares through tax-advantaged arrangements (such as a 401(k) plan or individual retirement account). After-tax returns are shown for Class III shares only; after-tax returns for other classes will vary.Updated performance information for the Fund is available at www.gmo.com. Past performance (before and after taxes) is not an indication of future performance.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns <span style="color:#000000;font-family:Times New Roman;font-size:10pt;margin-left:3.76%;">The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">annual total returns from year to year for the periods indicated and by comparing the Fund’s average annual total returns for different calendar periods with those of a broad-based index.</span>
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">www.gmo.com</span>
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Past performance (before and after taxes) is not an </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">indication of future performance.</span>
Bar Chart [Heading] rr_BarChartHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Annual Total Returns/Class III Shares</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Years Ending December 31</span>
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Highest Quarter: 13.07% 4Q 2022
Lowest Quarter: -4.35% 3Q 2022
Year-to-Date: 5.74% As of 3/31/2024

Performance Table Heading rr_PerformanceTableHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Average Annual Total Returns</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Periods Ending December 31, 2023</span>
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.</span>
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred <span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns shown are not </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">relevant if you are tax-exempt or if you hold your Fund shares through tax-advantaged arrangements (such as a 401(k) plan or individual retirement account). </span>
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax returns are shown for Class III shares only; after-tax returns for other classes will vary.</span>
GMO Small Cap Quality Fund | Risk Lose Money [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Many factors can affect this value, and you may lose money by investing in the Fund.
GMO Small Cap Quality Fund | Market Risk Equities [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Market Risk – Equities – The market price of an equity in the Fund’s portfolio may decline due to factors affecting the issuer or its industry or the economy and equity markets generally. If the Fund purchases an equity for less than its fundamental fair (or intrinsic) value as assessed by GMO, the Fund runs the risk that the market price of the equity will not appreciate or will decline, (for example, if GMO’s assessment proves to be incorrect or the market fails to recognize the equity’s intrinsic value). The Fund also may purchase equities that typically trade at higher multiples of current earnings than other securities, and the market prices of these equities often are more sensitive to changes in future earnings expectations and interest rates than the market prices of equities trading at lower multiples. Declines in stock market prices generally are likely to reduce the net asset value of the Fund’s shares.
GMO Small Cap Quality Fund | Management and Operational Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Management and Operational Risk – The Fund runs the risk that GMO’s investment techniques will fail to produce intended results.GMO uses quantitative models as part of its investment process. GMO’s models may not accurately predict future market movements. In addition, GMO’s models rely on assumptions and data that are subject to limitations (e.g., inaccuracies, staleness) that could adversely affect their predictive value.
GMO Small Cap Quality Fund | Smaller Company Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Smaller Company Risk – Small-cap companies may have limited product lines, markets, or financial resources, lack the competitive strength of larger companies, have less experienced managers or depend on a few key employees. The securities of small-cap companies often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than the securities of companies with larger market capitalizations.
GMO Small Cap Quality Fund | Focused Investment Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Focused Investment Risk – Investments in countries, regions, asset classes, sectors, industries, currencies, or issuers that are subject to the same or similar risk factors and investments whose market prices are closely correlated are subject to higher overall risk than investments that are more diversified or whose market prices are not as closely correlated.
GMO Small Cap Quality Fund | Illiquidity Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Illiquidity Risk – Low trading volume, lack of a market maker, large position size, or legal restrictions increase the risk that the Fund or an underlying fund is limited or prevented from selling particular securities or closing derivative positions at desirable prices at a particular time or at all.
GMO Small Cap Quality Fund | Derivatives and Short Sales Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Derivatives and Short Sales Risk – The use of derivatives involves the risk that their value may not change as expected relative to changes in the value of the underlying assets, pools of assets, rates, currencies or indices. Derivatives also present other risks, including market risk, illiquidity risk, currency risk, credit risk, leveraging risk, commodities risk and counterparty risk. The market price of an option is affected by many factors, including changes in the market prices or dividend rates of underlying securities (or in the case of indices, the securities in such indices); the time remaining before expiration; changes in interest rates or exchange rates; and changes in the actual or perceived volatility of the relevant index or underlying securities. The Fund typically creates short investment exposure by selling securities short or by taking a derivative position in which the value of the derivative moves in the opposite direction from the price of an underlying asset, pool of assets, rate, currency or index. Specifically, the net asset value of the Fund’s shares will be adversely affected if the equities or other assets that are the subject of the Fund’s short exposures appreciate in value. The risk of loss associated with derivatives that provide short investment exposure and short sales of securities is theoretically unlimited.
GMO Small Cap Quality Fund | Counterparty Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Counterparty Risk – The Fund runs the risk that the counterparty to a derivatives contract or a clearing member used by the Fund to hold a cleared derivatives contract is unable or unwilling to make timely settlement payments, return the Fund’s collateral or otherwise honor its obligations.
GMO Small Cap Quality Fund | Leveraging Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Leveraging Risk – The use of derivatives, short sales and securities lending can create leverage. Leverage increases the Fund’s losses when the value of its investments (including derivatives) declines. In addition, the Fund’s portfolio will be leveraged if it exercises its right to delay payment on a redemption and the value of the Fund’s assets declines between the time a redemption request is treated as being received by the Fund and the time the Fund liquidates assets to fund that redemption.
GMO Small Cap Quality Fund | Market Disruption and Geopolitical Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Market Disruption and Geopolitical Risk – Geopolitical and other events (e.g., wars, pandemics, sanctions, terrorism) often disrupt securities markets and adversely affect the general economy or particular economies and markets. Those events, as well as other changes in non-U.S. and U.S. economic and political conditions, could exacerbate other risks or otherwise reduce the value of the Fund’s investments.
GMO Small Cap Quality Fund | Large Shareholder Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Large Shareholder Risk – To the extent that a large number of shares of the Fund is held by a single shareholder (e.g., an institutional investor or another GMO Fund) or a group of shareholders with a common investment strategy (e.g., GMO asset allocation accounts), the Fund is subject to the risk that a redemption by that shareholder or group will require the Fund to sell investments at disadvantageous prices, disrupt the Fund’s operations, or force the Fund’s liquidation.
GMO Small Cap Quality Fund | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.96%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.75%
1 Year rr_ExpenseExampleYear01 $ 77
3 Years rr_ExpenseExampleYear03 285
5 Years rr_ExpenseExampleYear05 510
10 Years rr_ExpenseExampleYear10 $ 1,159
2023 rr_AnnualReturn2023 32.66%
Year to Date Return, Label rr_YearToDateReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Year-to-Date:</span>
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Mar. 31, 2024
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 5.74%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Highest Quarter:</span>
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2022
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 13.07%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Lowest Quarter:</span>
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2022
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (4.35%)
1 Year rr_AverageAnnualReturnYear01 32.66%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 21.91%
Inception Date rr_AverageAnnualReturnInceptionDate Nov. 15, 2022
GMO Small Cap Quality Fund | Class IV  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.70% [1]
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.91%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.70%
1 Year rr_ExpenseExampleYear01 $ 72
3 Years rr_ExpenseExampleYear03 269
5 Years rr_ExpenseExampleYear05 483
10 Years rr_ExpenseExampleYear10 $ 1,100
GMO Small Cap Quality Fund | Class V  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.685% [1]
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.90%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.69%
1 Year rr_ExpenseExampleYear01 $ 70
3 Years rr_ExpenseExampleYear03 266
5 Years rr_ExpenseExampleYear05 478
10 Years rr_ExpenseExampleYear10 $ 1,089
GMO Small Cap Quality Fund | Class VI  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.655% [1]
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.87%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.66%
1 Year rr_ExpenseExampleYear01 $ 67
3 Years rr_ExpenseExampleYear03 257
5 Years rr_ExpenseExampleYear05 462
10 Years rr_ExpenseExampleYear10 $ 1,053
1 Year rr_AverageAnnualReturnYear01 32.79%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 32.72%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 20, 2022
GMO Small Cap Quality Fund | Class R6  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.96%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.75%
1 Year rr_ExpenseExampleYear01 $ 77
3 Years rr_ExpenseExampleYear03 285
5 Years rr_ExpenseExampleYear05 510
10 Years rr_ExpenseExampleYear10 $ 1,159
GMO Small Cap Quality Fund | Class I  
Risk Return Abstract rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Other expenses rr_OtherExpensesOverAssets 0.31% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 1.06%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.21%) [1],[2],[3]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.85%
1 Year rr_ExpenseExampleYear01 $ 87
3 Years rr_ExpenseExampleYear03 316
5 Years rr_ExpenseExampleYear05 564
10 Years rr_ExpenseExampleYear10 $ 1,275
1 Year rr_AverageAnnualReturnYear01 32.58%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 21.83%
Inception Date rr_AverageAnnualReturnInceptionDate Nov. 15, 2022
GMO Small Cap Quality Fund | Return After Taxes on Distributions | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 22.60%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 13.63%
GMO Small Cap Quality Fund | Return After Taxes on Distributions and Sale of Shares | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 19.09%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 13.09%
GMO Small Cap Quality Fund | S&P 600 Index (returns reflect no deduction for fees, expenses, or taxes) | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.05%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 8.04%
GMO Small Cap Quality Fund | S&P 600 Index (returns reflect no deduction for fees, expenses, or taxes) | Class VI  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.05%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 14.01%
GMO Small Cap Quality Fund | S&P 600 Index (returns reflect no deduction for fees, expenses, or taxes) | Class I  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.05%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception 8.04%
[1] Includes both management fee of 0.60% and class-specific shareholder service fee, if any, for each class of shares. For additional information about the shareholder service fee applicable to each class of shares of the Fund, please see the table included in the section of the Prospectus entitled “Multiple Classes and Eligibility.” Grantham, Mayo, Van Otterloo & Co. LLC (“GMO”) has contractually agreed to waive its fees with respect to and/or reimburse the Fund to the extent that the Fund’s total annual fund operating expenses (after applying all other contractual and voluntary expense limitation arrangements in effect at the time) exceed the following amounts for each class of shares, in each case representing the average daily net assets for the indicated class of shares: 0.75% for Class III shares; 0.70% for Class IV shares; 0.685% for Class V shares; 0.655% for Class VI shares; 0.75% for Class R6 shares; and 0.75% for Class I shares (each, an “Expense Cap”). Fees and expenses of the “non-interested” Trustees and legal counsel to the “non-interested” Trustees, investment-related costs (such as brokerage commissions, interest, and acquired fund fees and expenses), payments out of assets attributable to Class I shares for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries, taxes, litigation and indemnification expenses, judgments, and other extraordinary or non-recurring expenses not incurred in the ordinary course of the Fund’s business, are excluded from the Expense Cap. GMO also has contractually agreed to waive or reduce the Fund’s management fees and shareholder service fees to the extent necessary to offset the management fees and shareholder service fees paid to GMO that are directly or indirectly borne by the Fund or a class of shares of the Fund as a result of the Fund’s direct or indirect investments in other series of GMO Trust (“GMO Funds”). Management fees and shareholder service fees will not be waived below zero. These reimbursements and waivers will continue through at least June 30, 2025 and may not be terminated prior to this date without the action or consent of the Trust’s Board of Trustees.
[2] Includes payments for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries for the benefit of Class I shareholders. GMO has contractually agreed to waive its fees with respect to and/or reimburse Class I shares to the extent that amounts paid by the Fund out of the net assets attributable to Class I shares for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries for the benefit of Class I shareholders exceed 0.15% of the average daily net assets attributable to Class I shares. This reimbursement will continue through at least June 30, 2025 and may not be terminated prior to this date without the action or consent of the Trust’s Board of Trustees.
[3] GMO has voluntarily determined to waive its fees with respect to and/or reimburse Class I shares for all amounts paid by the Fund out of the net assets attributable to Class I shares for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries for the benefit of Class I shareholders. GMO may terminate this waiver/reimbursement at any time.