Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	GMO TRUST
Prospectus Date	rr_ProspectusDate	Jun. 30, 2016
GMO Resources Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	GMO RESOURCES FUND
Objective [Heading]	rr_ObjectiveHeading	Investment objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Total return.
Expense [Heading]	rr_ExpenseHeading	Fees and expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The tables below describe the fees and expenses that you may bear for each class of shares if you buy and hold shares of the Fund.
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 bear each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	June 30, 2017
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. A higher portfolio turnover rate may result in higher transaction costs and, when Fund shares are held in a taxable account, higher 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, 2016, the Fund’s portfolio turnover rate (excluding short-term investments) was 130% of the average value of its portfolio. 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, 2016, excluding transactions in U.S. Treasury Fund, was 92% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	130.00%
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. 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:
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	If you sell your shares
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	If you do not sell your shares
Strategy [Heading]	rr_StrategyHeading	Principal investment strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	GMO seeks to achieve the Fund’s investment objective by investing primarily in securities of companies in the natural resources sector (as defined below). Given the limited supply of many natural resources and the expected growth and industrialization of countries that are not members of the Organisation for Economic Co-operation and Development (OECD), GMO believes global demand for many natural resources, and therefore prices of these natural resources generally, will increase over a long time period. In managing the Fund, GMO seeks to invest in the securities of companies that it believes will benefit from this expected long-term rise in natural resource prices. GMO selects the securities the Fund should buy or sell based on its evaluation of companies’ published financial information and corporate behavior, securities’ prices, commodities’ prices, equity and bond markets, the overall global economy, and governmental policies. In selecting securities for the Fund, GMO uses a combination of investment methods to identify securities that GMO believes have positive return potential relative to other securities of companies in the natural resources sector. Some of these methods evaluate individual securities or groups of securities based on the ratio of their price to historical financial information and forecasted financial information, such as book value, cash flow and earnings, and a comparison of these ratios to industry or market averages or to their own history. Other methods focus on patterns of information, such as price movement or volatility of a security or groups of securities relative to other stocks in the natural resources sector. At times, the Fund may have substantial exposure to a single asset class, industry, sector, country, or region. The Fund may invest in securities of companies of any market capitalization. The Fund also may engage in merger arbitrage transactions. 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, and as a substitute for securities lending. Derivatives used may include futures, options, and swap contracts. In addition, the Fund may lend its portfolio securities. The Fund has a fundamental policy to concentrate its investments in the natural resources sector, and, under normal market conditions, the Fund invests at least 80% of its assets in the securities of companies in that sector. The Fund considers the “natural resources sector” to include companies that own, produce, refine, process, transport, and market natural resources and companies that provide related equipment, infrastructure, and services. The sector includes, for example, the following industries: integrated oil, oil and gas exploration and production, gold and other precious metals, steel and iron ore production, energy services and technology, base metal production, forest products, farming products, paper products, chemicals, building materials, coal, water, alternative energy sources, and environmental services. The Fund is permitted to invest directly and indirectly (e.g., through underlying funds or derivatives) in securities of companies tied economically to any country in the world, including emerging countries. In addition to its investments in companies in the natural resources sector, the Fund also may invest up to 20% of its net assets in securities of any type of company. The Fund also may invest in U.S. Treasury Fund, in money market funds unaffiliated with GMO, or directly in the types of investments typically held by money market funds.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	The Fund has a fundamental policy to concentrate its investments in the natural resources sector, and, under normal market conditions, the Fund invests at least 80% of its assets in the securities of companies in that sector.
Risk [Heading]	rr_RiskHeading	Principal risks of investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The value of the Fund’s shares changes with the value of the Fund’s investments. Many factors can affect this value, and you may lose money by investing in the Fund. The Fund is a non-diversified investment company under the Investment Company Act of 1940, as amended, and therefore a decline in the market price of a particular security held by the Fund may affect the Fund’s performance more than if the Fund were a diversified investment company. The principal risks of investing in the Fund are summarized below. For a more complete discussion of these risks, see “Description of Principal Risks.” Focused Investment Risk – By concentrating its investments in the natural resources sector, the Fund is particularly exposed to adverse developments, including adverse price movements, affecting issuers in that sector and is subject to greater risks than a fund that invests in a wider range of industries. In addition, the market prices of securities of companies in the natural resources sector are often more volatile than securities of companies in other industries. Some of the commodities used as raw materials or produced by these companies are subject to broad price fluctuations as a result of industry-wide supply and demand factors. Companies in the natural resources sector often have limited pricing power over supplies or for the products they sell and that can affect their profitability, and are often capital-intensive and use significant amounts of leverage. Projects in the natural resources sector may have long setup times, and companies cannot ensure that the market will be favorable at the time the project begins production. Companies in the natural resources sector also may be subject to special risks associated with natural or man-made disasters. In addition, the natural resources sector can be especially affected by events relating to international political and economic developments, government regulations, energy conservation, and the success of exploration projects. Because the Fund invests primarily in the natural resources sector, it runs the risk of performing poorly during an economic downturn or a decline in demand for natural resources. Commodities Risk – Commodity prices can be extremely volatile, and exposure to commodities can cause the net asset value of the Fund’s shares to decline or fluctuate more than if the Fund had a broader range of investments. Market Risk – Equities – The market price of an equity may decline due to factors affecting the issuer, 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 determined by GMO, the Fund runs the risk that the market price of the equity will not appreciate or will decline due to GMO’s incorrect assessment of the equity’s fundamental fair (or 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 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. Management and Operational Risk – The Fund runs the risk that GMO’s investment techniques will fail to produce desired results. GMO often uses quantitative models as part of its investment process. GMO’s models are not necessarily predictive of future market events and use simplifying assumptions that can limit their effectiveness. In addition, the data on which the models are based is subject to limitations (e.g., inaccuracies, staleness) that could adversely affect the Fund’s performance. The Fund also runs the risk that GMO’s assessment of an investment (including a company’s fundamental fair (or intrinsic) value) may be wrong or that deficiencies in GMO’s or another service provider’s internal systems or controls will cause losses for the Fund or impair Fund operations. Non-U.S. Investment Risk – The market prices of many non-U.S. securities fluctuate more than those of U.S. securities. Many non-U.S. securities markets are less stable, smaller, less liquid, and less regulated than U.S. securities markets, and the cost of trading in those markets often is higher than in U.S. securities markets. Transactions in non-U.S. securities generally involve higher commission rates, transfer taxes, and custodial costs than similar transactions in U.S. securities. In addition, the Fund may be subject to non-U.S. taxes, including potentially on a retroactive basis, on (i) capital gains it realizes or dividends, interest, or other amounts it realizes or accrues in respect of non-U.S. investments; (ii) transactions in those investments; and (iii) repatriation of proceeds generated from the sale or other disposition of those investments. Also, the Fund needs a license to invest directly in many non-U.S. securities markets, and the Fund is subject to the risk that it could not invest if its license were terminated or suspended. In some non-U.S. securities markets, prevailing custody and trade settlement practices (e.g., the requirement to pay for securities prior to receipt) expose the Fund to credit and other risks. Further, adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. These and other risks (e.g., nationalization, expropriation or other confiscation of assets of non-U.S. issuers) tend to be greater for investments in companies tied economically to emerging countries, the economies of which may be predominantly based on only a few industries or dependent on revenues from particular commodities and which often are more volatile than the economies of developed countries. Market Disruption and Geopolitical Risk – Geopolitical and other events may disrupt securities markets and adversely affect global economies and markets. Those events, as well as other changes in non-U.S. and U.S. economic and political conditions, could adversely affect the value of the Fund’s investments. Currency Risk – Fluctuations in exchange rates can adversely affect the market value of the Fund’s foreign currency holdings and investments denominated in foreign currencies. Illiquidity Risk – Low trading volume, lack of a market maker, large position size, or legal restrictions may limit or prevent the Fund from selling particular securities or closing derivative positions at desirable prices. Small Company Risk – Smaller companies may have limited product lines, markets, or financial resources, may lack the competitive strength of larger companies, may have inexperienced managers or may depend on a few key employees. The securities of companies with smaller market capitalizations 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. 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, rates, or indices. Derivatives also present other risks, including market risk, illiquidity risk, currency risk, credit 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 stock market and underlying securities. The Fund may create short investment exposure by taking a derivative position in which the value of the derivative moves in the opposite direction from the price of an underlying investment, pool of investments, index or currency. The risks of loss associated with derivatives that provide short investment exposure and short sales of securities are theoretically unlimited. Counterparty Risk – The Fund runs the risk that the counterparty to a derivatives contract, a clearing member used by the Fund to hold a cleared derivatives contract, or a borrower of the Fund’s securities will be unable or unwilling to make timely settlement payments, return the Fund’s margin or otherwise honor its obligations. Leveraging Risk – The use of reverse repurchase agreements and other derivatives and securities lending creates leverage. Leverage increases the Fund’s losses when the value of its investments (including derivatives) declines. 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 those shareholders of all or a large portion of their Fund shares will require the Fund to sell securities at disadvantageous prices or otherwise disrupt the Fund’s operations. Merger Arbitrage Risk – If the Fund purchases securities in anticipation of a proposed merger, exchange offer, tender offer, or other similar transaction and that transaction later appears unlikely to be consummated or, in fact, is not consummated or is delayed, the market prices of the securities purchased by the Fund may decline sharply, resulting in losses to the Fund. The risk/reward payout of merger arbitrage strategies typically is asymmetric, as the losses in failed transactions often far exceed the gains in successful transactions. Merger arbitrage strategies are subject to the risk of overall market movements, and the Fund may experience losses even if a transaction is consummated.
Risk Lose Money [Text]	rr_RiskLoseMoney	Many factors can affect this value, and you may lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	The Fund is a non-diversified investment company under the Investment Company Act of 1940, as amended, and therefore a decline in the market price of a particular security held by the Fund may affect the Fund's performance more than if the Fund were a diversified investment company.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
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 the MSCI ACWI Commodity Producers Index and the MSCI ACWI. Purchase premiums and redemption fees are not reflected in the bar chart, but are reflected in the table; as a result, the returns in the table are lower than the returns in the bar chart. Returns in the table reflect current purchase premiums and redemption fees. 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	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 the MSCI ACWI Commodity Producers Index and the MSCI ACWI.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.gmo.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns/Class III Shares Years Ending December 31
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Purchase premiums and redemption fees are not reflected in the bar chart, but are reflected in the table; as a result, the returns in the table are lower than the returns in the bar chart.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarter: 12.84% (3Q2013) Lowest Quarter: – 20.51% (3Q2015) Year-to-Date (as of 3/31/16): 12.09%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns Periods Ending December 31, 2015
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	Returns in the table reflect current purchase premiums and redemption fees.
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	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).
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Class III shares only; after-tax returns for other classes will vary.
GMO Resources Fund | Class III
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.30%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.30%
Management fee	rr_ManagementFeesOverAssets	0.50%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.15%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.22%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.87%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.10%)	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	0.77%	[2]
1 Year	rr_ExpenseExampleYear01	$ 140
3 Years	rr_ExpenseExampleYear03	331
5 Years	rr_ExpenseExampleYear05	538
10 Years	rr_ExpenseExampleYear10	1,135
1 Year	rr_ExpenseExampleNoRedemptionYear01	108
3 Years	rr_ExpenseExampleNoRedemptionYear03	297
5 Years	rr_ExpenseExampleNoRedemptionYear05	501
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,090
2012	rr_AnnualReturn2012	10.30%
2013	rr_AnnualReturn2013	3.58%
2014	rr_AnnualReturn2014	(17.34%)
2015	rr_AnnualReturn2015	(22.02%)
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-Date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2016
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	12.09%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2013
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	12.84%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(20.51%)
1 Year	rr_AverageAnnualReturnYear01	(22.49%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(7.18%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 28, 2011
GMO Resources Fund | Class IV
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.30%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.30%
Management fee	rr_ManagementFeesOverAssets	0.50%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.10%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.23%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.83%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.11%)	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	0.72%	[2]
1 Year	rr_ExpenseExampleYear01	$ 135
3 Years	rr_ExpenseExampleYear03	317
5 Years	rr_ExpenseExampleYear05	515
10 Years	rr_ExpenseExampleYear10	1,087
1 Year	rr_ExpenseExampleNoRedemptionYear01	103
3 Years	rr_ExpenseExampleNoRedemptionYear03	283
5 Years	rr_ExpenseExampleNoRedemptionYear05	478
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,042
1 Year	rr_AverageAnnualReturnYear01	(22.44%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(12.95%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 20, 2013
GMO Resources Fund | Class V
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.30%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.30%
Management fee	rr_ManagementFeesOverAssets	0.50%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.085%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.23%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.82%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.11%)	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	0.71%	[2]
1 Year	rr_ExpenseExampleYear01	$ 133
3 Years	rr_ExpenseExampleYear03	314
5 Years	rr_ExpenseExampleYear05	510
10 Years	rr_ExpenseExampleYear10	1,075
1 Year	rr_ExpenseExampleNoRedemptionYear01	102
3 Years	rr_ExpenseExampleNoRedemptionYear03	280
5 Years	rr_ExpenseExampleNoRedemptionYear05	473
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,030
GMO Resources Fund | Class VI
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.30%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.30%
Management fee	rr_ManagementFeesOverAssets	0.50%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.055%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.23%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.79%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.11%)	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	0.68%	[2]
1 Year	rr_ExpenseExampleYear01	$ 130
3 Years	rr_ExpenseExampleYear03	304
5 Years	rr_ExpenseExampleYear05	493
10 Years	rr_ExpenseExampleYear10	1,040
1 Year	rr_ExpenseExampleNoRedemptionYear01	99
3 Years	rr_ExpenseExampleNoRedemptionYear03	271
5 Years	rr_ExpenseExampleNoRedemptionYear05	457
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 995
GMO Resources Fund | Return After Taxes on Distributions | Class III
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(22.90%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(8.47%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 28, 2011
GMO Resources Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class III
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(12.07%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(5.08%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 28, 2011
GMO Resources Fund | MSCI ACWI Commodity Producers Index (Fund benchmark) (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments) | Class III
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(25.83%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(9.33%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 28, 2011
GMO Resources Fund | MSCI ACWI Commodity Producers Index (Fund benchmark) (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments) | Class IV
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(25.83%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(13.75%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 20, 2013
GMO Resources Fund | MSCI ACWI (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments) | Class III
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.36%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	10.03%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 28, 2011
GMO Resources Fund | MSCI ACWI (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments) | Class IV
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.36%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	5.97%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 20, 2013

[1] Grantham, Mayo, Van Otterloo & Co. LLC ("GMO") has contractually agreed to reimburse the Fund for the portion of its "Specified Operating Expenses" (as defined below) that exceeds 0.10% of the Fund's average daily net assets. "Specified Operating Expenses" means only the following expenses: audit expenses, fund accounting expenses, pricing service expenses, expenses of non-investment related tax services, transfer agency expenses, expenses of non-investment related legal services provided to the Fund by or at the direction of GMO, federal securities law filing expenses, printing expenses, state and federal registration fees and custody expenses. 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. This reimbursement and waiver will continue through at least June 30, 2017, and may not be terminated prior to this date without the action or consent of the Fund's Board of Trustees.

[2] after expense reimbursement/waiver