Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	GMO TRUST
Prospectus Date	rr_ProspectusDate	Jun. 30, 2016
GMO Special Opportunities Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	GMO SPECIAL OPPORTUNITIES FUND
Objective [Heading]	rr_ObjectiveHeading	Investment objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Positive 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 (including the accounts of the Fund’s wholly-owned subsidiary, GMO Special Opportunities SPC Ltd., and excluding short-term investments) was 69% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	69.00%
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 generally uses a fundamental approach to identify investments that are, in GMO's judgment, trading below their fundamental fair (or intrinsic) value. GMO expects that the Fund's portfolio will consist of a limited number of investments. GMO does not manage the Fund to, or control the Fund's risk relative to, any securities index or securities benchmark. The factors GMO considers and investment methods GMO uses can change over time. The Fund may have long or short exposure to non-U.S. and U.S. equities (which may include emerging country equities and equities of any market capitalization), non-U.S. and U.S. fixed income instruments (which may include asset-backed securities and other fixed income instruments of any credit quality, including those that are below investment grade (commonly referred to as "junk bonds"), including distressed and defaulted debt securities, and having any maturity or duration), currencies, and, from time to time, other alternative instruments (e.g., instruments that seek exposure to, or reduce risks of, market volatility). The Fund may engage in merger arbitrage transactions. The Fund is not restricted in its exposure to any particular asset class and at times may be substantially exposed (long or short) to a single asset class (e.g., equities or fixed income securities). In addition, the Fund is not restricted in its exposure (long or short) to any particular market. The Fund may have substantial exposure (long or short) to securities of companies in a particular country or type of country (e.g., emerging countries). The Fund could be subject to material losses from a single investment. In pursuing its investment objective, the Fund may (but is not obligated to) invest in a wide variety of exchange-traded and over-the-counter (OTC) derivatives, including, without limitation, reverse repurchase agreements, options, futures, swap contracts (such as swaps on securities and securities indices, total return swaps, interest rate swaps, currency swaps, cross currency basis swaps, credit default swaps, variance swaps, commodity swaps, inflation swaps, and other types of swaps), swaptions, and foreign currency derivative transactions. In addition, the Fund may lend its portfolio securities. The Fund is not limited in its use of derivatives or in the total notional value of its derivative positions. As a result of its derivative positions, the Fund may have gross investment exposures in excess of its net assets (i.e., the Fund may be leveraged) and therefore is subject to heightened risk of loss. The Fund's performance can depend substantially, if not primarily, on the performance of assets or indices underlying its derivatives even though it does not own those assets or indices. The Fund may gain exposure to commodities and some other assets by investing through a wholly-owned subsidiary advised by GMO, which does not receive management or other fees for its services. The subsidiary invests primarily in commodity-related derivatives and fixed income securities but also may gain exposure to any other investment in which the Fund is permitted to invest directly. References in this Prospectus to the Fund may refer to actions undertaken by the subsidiary as well as the Fund. The Fund does not invest directly in commodities and commodity-related derivatives, but may do so indirectly through its subsidiary company (or otherwise). In seeking to achieve the Fund's investment objective, GMO may invest a significant portion of the Fund's net assets in cash and cash equivalents. GMO would not consider such investments to be "temporary defensive positions." 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.
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. References to investments include those held directly by the Fund and indirectly through the Fund’s investments in its wholly-owned subsidiary and in any underlying funds in which it invests. 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, including those risks to which the Fund is exposed as a result of its investments in its wholly-owned subsidiary and in any underlying funds, see “Description of Principal Risks.” Management and Operational Risk – The Fund runs the risk that GMO’s investment techniques will fail to produce desired results. 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. 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. Because the Fund normally does not take temporary defensive positions, declines in stock market prices generally are likely to reduce the net asset value of the Fund’s shares. Credit Risk – The Fund runs the risk that the issuer or guarantor of a fixed income investment or the obligor of an obligation underlying an asset-backed security will be unable or unwilling to satisfy its obligation to pay principal and interest or otherwise to honor its obligations in a timely manner. The market price of a fixed income investment will normally decline as a result of the issuer’s, guarantor’s, or obligor’s failure to meet its payment obligations, or in anticipation of such failure. Below investment grade securities have speculative characteristics, and changes in economic conditions or other circumstances are more likely to impair the ability of issuers of those securities to make principal and interest payments than is the case with issuers of investment grade securities. Investments in distressed or defaulted or other low quality debt securities generally are considered speculative and may involve substantial risks not normally associated with investments in higher quality securities, including adverse business, financial or economic conditions that lead to payment defaults and insolvency proceedings on the part of their issuers. In particular, distressed or defaulted obligations might be repaid, if at all, only after lengthy workout or bankruptcy proceedings, during which the issuer might not make any interest or other payments, and the Fund may incur additional expenses to seek recovery. If GMO’s assessment of the eventual recovery value of a distressed or defaulted debt security proves incorrect, the Fund may lose a substantial portion or all of its investment or may be required to accept cash or instruments worth less than its original investment. Market Risk – Fixed Income Investments – The market price of a fixed income investment can decline due to market-related factors, including rising interest rates and widening credit spreads, or decreased liquidity stemming from the market’s uncertainty about the value of a fixed income investment (or class of fixed income investments). 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. 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. 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 reduce the value of the Fund’s investments. Focused Investment Risk – Investments focused in a limited number of countries, regions, sectors, industries, or issuers that are subject to the same or similar risk factors and investments whose prices are closely correlated are subject to greater overall risk than investments that are more diversified or whose prices are not as closely correlated. 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. 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. 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. 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. 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. 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 in a rapid and unpredictable manner. Market Risk – Asset-Backed Securities – The market price of fixed income investments with complex structures, such as asset-backed securities, can decline due to a variety of factors, including market uncertainty about their credit quality and the reliability of their payment streams. Payment streams associated with asset-backed securities held by the Fund depend on many factors (e.g., the cash flow generated by the assets backing the securities, the deal structure, the creditworthiness of any credit-support provider, and the reliability of various other service providers with access to the payment stream), and a problem in any one of these factors can lead to a reduction in the payment stream GMO expected the Fund to receive at the time the Fund purchased the asset-backed security. 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. 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. Fund of Funds Risk – The Fund is indirectly exposed to all of the risks of an investment in its wholly-owned subsidiary and in any underlying funds in which it invests, including the risk that its wholly-owned subsidiary or those underlying funds will not perform as expected.
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 Barclays U.S. Treasury Inflation Notes: 1-10 Years Index and the Consumer Price Index. 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). 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 Barclays U.S. Treasury Inflation Notes: 1-10 Years Index and the Consumer Price Index.
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 VI 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: 3.21% (4Q2015) Lowest Quarter: – 3.83% (3Q2015) Year-to-Date (as of 3/31/16): 1.28%
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).
GMO Special Opportunities Fund | Class III
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.50%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.50%
Management fee	rr_ManagementFeesOverAssets	1.10%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.15%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.14%
Acquired fund fees and expenses (underlying fund expenses)	rr_AcquiredFundFeesAndExpensesOverAssets	0.04%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.43%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	1.43%	[3]
1 Year	rr_ExpenseExampleYear01	$ 246
3 Years	rr_ExpenseExampleYear03	555
5 Years	rr_ExpenseExampleYear05	887
10 Years	rr_ExpenseExampleYear10	1,825
1 Year	rr_ExpenseExampleNoRedemptionYear01	195
3 Years	rr_ExpenseExampleNoRedemptionYear03	500
5 Years	rr_ExpenseExampleNoRedemptionYear05	828
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,755
GMO Special Opportunities Fund | Class IV
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.50%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.50%
Management fee	rr_ManagementFeesOverAssets	1.10%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.10%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.14%
Acquired fund fees and expenses (underlying fund expenses)	rr_AcquiredFundFeesAndExpensesOverAssets	0.04%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.38%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	1.38%	[3]
1 Year	rr_ExpenseExampleYear01	$ 241
3 Years	rr_ExpenseExampleYear03	540
5 Years	rr_ExpenseExampleYear05	861
10 Years	rr_ExpenseExampleYear10	1,770
1 Year	rr_ExpenseExampleNoRedemptionYear01	190
3 Years	rr_ExpenseExampleNoRedemptionYear03	485
5 Years	rr_ExpenseExampleNoRedemptionYear05	801
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,699
GMO Special Opportunities Fund | Class V
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.50%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.50%
Management fee	rr_ManagementFeesOverAssets	1.10%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.085%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.14%
Acquired fund fees and expenses (underlying fund expenses)	rr_AcquiredFundFeesAndExpensesOverAssets	0.04%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.37%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	1.37%	[3]
1 Year	rr_ExpenseExampleYear01	$ 240
3 Years	rr_ExpenseExampleYear03	537
5 Years	rr_ExpenseExampleYear05	856
10 Years	rr_ExpenseExampleYear10	1,759
1 Year	rr_ExpenseExampleNoRedemptionYear01	189
3 Years	rr_ExpenseExampleNoRedemptionYear03	482
5 Years	rr_ExpenseExampleNoRedemptionYear05	796
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,688
GMO Special Opportunities Fund | Class VI
Risk/Return:	rr_RiskReturnAbstract
Purchase premium (as a percentage of amount invested)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	0.50%
Redemption fee (as a percentage of amount redeemed)	rr_RedemptionFeeOverRedemption	0.50%
Management fee	rr_ManagementFeesOverAssets	1.10%	[1]
Shareholder service fee	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.055%	[1]
Other expenses	rr_OtherExpensesOverAssets	0.14%
Acquired fund fees and expenses (underlying fund expenses)	rr_AcquiredFundFeesAndExpensesOverAssets	0.04%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.34%
Expense reimbursement/waiver	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses	rr_NetExpensesOverAssets	1.34%	[3]
1 Year	rr_ExpenseExampleYear01	$ 237
3 Years	rr_ExpenseExampleYear03	528
5 Years	rr_ExpenseExampleYear05	840
10 Years	rr_ExpenseExampleYear10	1,726
1 Year	rr_ExpenseExampleNoRedemptionYear01	186
3 Years	rr_ExpenseExampleNoRedemptionYear03	472
5 Years	rr_ExpenseExampleNoRedemptionYear05	780
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,655
2015	rr_AnnualReturn2015	2.25%
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	1.28%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2015
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	3.21%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.83%)
1 Year	rr_AverageAnnualReturnYear01	1.23%
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(0.59%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 28, 2014
GMO Special Opportunities Fund | Return After Taxes on Distributions | Class VI
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.51%
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(1.10%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 28, 2014
GMO Special Opportunities Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class VI
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.00%
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(0.56%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 28, 2014
GMO Special Opportunities Fund | Barclays U.S. Treasury Inflation Notes: 1-10 Year Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.52%)
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(2.42%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 28, 2014
GMO Special Opportunities Fund | Consumer Price Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.72%
5 Years	rr_AverageAnnualReturnYear05
10 Years	rr_AverageAnnualReturnYear10
Incept.	rr_AverageAnnualReturnSinceInception	(0.01%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 28, 2014

[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] These indirect expenses include commissions paid to brokers by the Fund for executing transactions in unaffiliated underlying funds (“transaction fees”). Net fees and expenses of underlying funds (before addition of transaction fees) and indirect transaction fees were approximately 0.03% and 0.01%, respectively.

[3] after expense reimbursement/waiver (Fund and underlying fund expenses)