v3.26.3
Label Element Value
MFS International Intrinsic Equity Fund  
Risk/Return: oef_RiskReturnAbstract  
Risk/Return [Heading] oef_RiskReturnHeading MFS® International Intrinsic Equity Fund Summary of Key Information
Objective [Heading] oef_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] oef_ObjectivePrimaryTextBlock

The fund’s investment objective is to seek capital appreciation.

Expense Heading [Optional Text] oef_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] oef_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.

You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $50,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus.

Shareholder Fees Caption [Optional Text] oef_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Optional Text] oef_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading] oef_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] oef_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These transaction 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 21% of the average value of its portfolio.
Portfolio Turnover, Rate oef_PortfolioTurnoverRate 21.00%
Expense Breakpoint Discounts [Text] oef_ExpenseBreakpointDiscounts You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $50,000 in MFS funds.
Expense Breakpoint, Minimum Investment Required [Amount] oef_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example [Heading] oef_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] oef_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 you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same.

Expense Example by, Year, Caption [Text] oef_ExpenseExampleByYearCaption Although your actual costs will likely be higher or lower, under these assumptions your costs would be:
Strategy [Heading] oef_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] oef_StrategyNarrativeTextBlock

MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the fund’s net assets in equity securities. Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer.

MFS normally invests the fund’s assets primarily in foreign securities, including emerging market securities. Emerging market countries are countries with financial and capital markets in the development phase. Emerging market countries include countries located in Latin America, Asia, Africa, the Middle East, and developing countries of Europe, primarily Eastern Europe.

In selecting investments for the fund, MFS is not constrained by any particular investment style. MFS may invest the fund’s assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies), in the stocks of companies it believes are undervalued compared to their perceived worth (value companies), or in a combination of growth and value companies. In managing the fund, MFS assesses the intrinsic valuation of issuers by considering the full context of how a company's cash flows are generated. MFS focuses on companies it believes have conservative balance sheets, sustainable competitive advantages, high returns on capital, and/or the ability to weather economic downturns, among other factors. Many of the factors considered by MFS in assessing issuers are qualitative in nature and require subjective judgment and interpretation.

MFS may invest the fund’s assets in securities of companies of any size.

MFS normally invests the fund's assets across different industries, sectors, countries, and regions, but MFS may invest a significant percentage of the fund’s assets in issuers in a single industry, sector, country, or region.

While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease currency exposure. Derivatives include futures, forward contracts, options, and swaps.

MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual issuers. Quantitative screening tools that systematically evaluate issuers may also be considered.

For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.

Summary of Definition of Rule 35d-1 Term in Fund Name [Text Block] fnd_NmRule35d1TermDfnSmryTextBlock Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer.
Rule 35d-1 Eighty Percent Investment Policy [Text Block] fnd_NmRule35d1EightyPctInvstmntPlcyTextBlock MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the fund’s net assets in equity securities.
Bar Chart and Performance Table [Heading] oef_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] oef_PerformanceNarrativeTextBlock

The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of (i) a broad measure of market performance and (ii) one or more other measures of performance for markets in which the fund invests.

The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at mfs.com or by calling 1-800-225-2606.
Performance Information Illustrates Variability of Returns [Text] oef_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of (i) a broad measure of market performance and (ii) one or more other measures of performance for markets in which the fund invests.
Performance Availability Phone [Text] oef_PerformanceAvailabilityPhone 1-800-225-2606
Performance Availability Website Address [Text] oef_PerformanceAvailabilityWebSiteAddress mfs.com
Performance Past Does Not Indicate Future [Text] oef_PerformancePastDoesNotIndicateFuture The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future.
Bar Chart [Heading] oef_BarChartHeading Class A Bar Chart.
Bar Chart Narrative [Text Block] oef_BarChartNarrativeTextBlock The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown.
Bar Chart Does Not Reflect Sales Loads [Text] oef_BarChartDoesNotReflectSalesLoads The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown.
Bar Chart Closing [Text Block] oef_BarChartClosingTextBlock

The total return for the six-month period ended June 30, 2026, was 4.91%. During the period(s) shown in the bar chart, the highest quarterly return was 16.58% (for the calendar quarter ended June 30, 2020) and the lowest quarterly return was (15.15)% (for the calendar quarter ended June 30, 2022).
Performance Table Heading oef_PerformanceTableHeading Performance Table.
Index No Deduction for Fees, Expenses, or Taxes [Text] oef_IndexNoDeductionForFeesExpensesTaxes Reflects no deduction for fees, expenses, or taxes
Performance Table Not Relevant to Tax Deferred oef_PerformanceTableNotRelevantToTaxDeferred Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] oef_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.
Performance Table Closing [Text Block] oef_PerformanceTableClosingTextBlock

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.
Average Annual Return, Caption [Optional Text] oef_AverageAnnualReturnCaption Average Annual Total Returns (For the Periods Ended December 31, 2025)
MFS International Intrinsic Equity Fund | Principal Risks  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Principal Risks

As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.

The principal risks of investing in the fund are:
MFS International Intrinsic Equity Fund | Risk Lose Money [Member]  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund.
MFS International Intrinsic Equity Fund | Risk Not Insured [Member]  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
MFS International Intrinsic Equity Fund | Investment Selection Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Investment Selection Risk: MFS' investment analysis, including its assessment of the intrinsic valuation of issuers, and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results.

MFS International Intrinsic Equity Fund | Equity Market Risk/Company Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Equity Market Risk/Company Risk: Equity markets are volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single issuer or type of security, issuers within a broad market sector, industry or geographic region, or the equity markets in general. Certain events can have a dramatic adverse effect on equity markets and may lead to periods of high volatility in an equity market or a segment of an equity market. The value of an investment held by the fund may decline due to factors directly related to the issuer.

 
MFS International Intrinsic Equity Fund | Foreign Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Foreign Risk: Exposure to foreign markets through issuers or currencies can involve additional risks relating to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These factors can make foreign investments, especially those tied economically to emerging markets or countries subject to sanctions or the threat of new or modified sanctions, more volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to these conditions than the U.S. market.

MFS International Intrinsic Equity Fund | Emerging Markets Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Emerging Markets Risk: Investments tied economically to emerging markets, especially frontier markets, can involve additional and greater risks than the risks associated with investments in developed markets. Emerging markets can have less developed markets, greater custody and operational risk, less developed legal, regulatory, and accounting systems, greater government involvement in the economy, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater political, social, geopolitical, and economic instability than developed markets.

MFS International Intrinsic Equity Fund | Currency Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Currency Risk: The value of foreign currencies relative to the U.S. dollar fluctuates in response to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions, and changes in currency exchange rates impact the financial condition of companies or other issuers and may change the value in U.S. dollars of investments denominated in foreign currencies.

MFS International Intrinsic Equity Fund | Focus Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Focus Risk: Issuers in a single industry, sector, country, or region can react similarly to market, currency, political, economic, regulatory, geopolitical, environmental, public health, and other conditions, and the fund's performance will be affected by the conditions in the industries, sectors, countries, and regions to which the fund is exposed. Furthermore, investments in particular industries, sectors, countries, or regions may be more volatile than the broader market as a whole.

MFS International Intrinsic Equity Fund | Derivatives Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Derivatives Risk: Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.
MFS International Intrinsic Equity Fund | Leveraging Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Leveraging Risk: Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses.

MFS International Intrinsic Equity Fund | Counterparty and Third Party Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Counterparty and Third Party Risk: Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.
MFS International Intrinsic Equity Fund | Liquidity Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Liquidity Risk: It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs.

MFS International Intrinsic Equity Fund | Large Shareholder Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Large Shareholder Risk: From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.
MFS International Intrinsic Equity Fund | MSCI EAFE (Europe, Australasia, Far East) Index (net div)  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel MSCI EAFE (Europe, Australasia, Far East) Index (net div)
Average Annual Return, Percent oef_AvgAnnlRtrPct 31.22%
Average Annual Return, Percent oef_AvgAnnlRtrPct 8.92%
Average Annual Return, Percent oef_AvgAnnlRtrPct 8.18%
MFS International Intrinsic Equity Fund | MSCI EAFE (Europe, Australasia, Far East) Value Index (net div)  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel MSCI EAFE (Europe, Australasia, Far East) Value Index (net div)
Average Annual Return, Percent oef_AvgAnnlRtrPct 42.25%
Average Annual Return, Percent oef_AvgAnnlRtrPct 13.36%
Average Annual Return, Percent oef_AvgAnnlRtrPct 8.69%
MFS International Intrinsic Equity Fund | Class A  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MGIAX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 1.00% [1]
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.00%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.99%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expenses Deferred Charges [Text Block] oef_ExpensesDeferredChargesTextBlock This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase.
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 670
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 874
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 1,095
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,728
Year to Date Return, Label [Optional Text] oef_YearToDateReturnLabel The total return for the six-month period ended
Bar Chart, Year to Date Return, Date oef_BarChartYearToDateReturnDate Jun. 30, 2026
Bar Chart, Year to Date Return oef_BarChartYearToDateReturn 4.91%
Highest Quarterly Return, Label [Optional Text] oef_HighestQuarterlyReturnLabel highest quarterly return
Highest Quarterly Return, Date oef_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return oef_BarChartHighestQuarterlyReturn 16.58%
Lowest Quarterly Return, Label [Optional Text] oef_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date oef_BarChartLowestQuarterlyReturnDate Jun. 30, 2022
Lowest Quarterly Return oef_BarChartLowestQuarterlyReturn (15.15%)
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 25.17%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.95%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.20%
Annual Return [Percent] oef_AnnlRtrPct 3.93%
Annual Return [Percent] oef_AnnlRtrPct 26.83%
Annual Return [Percent] oef_AnnlRtrPct (9.22%)
Annual Return [Percent] oef_AnnlRtrPct 25.56%
Annual Return [Percent] oef_AnnlRtrPct 20.15%
Annual Return [Percent] oef_AnnlRtrPct 10.29%
Annual Return [Percent] oef_AnnlRtrPct (23.26%)
Annual Return [Percent] oef_AnnlRtrPct 17.64%
Annual Return [Percent] oef_AnnlRtrPct 7.15%
Annual Return [Percent] oef_AnnlRtrPct 32.80%
MFS International Intrinsic Equity Fund | Class A | After Taxes on Distributions  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns After Taxes on Distributions
Average Annual Return, Percent oef_AvgAnnlRtrPct 22.96%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.57%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.58%
MFS International Intrinsic Equity Fund | Class A | After Taxes on Distributions and Sales  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent oef_AvgAnnlRtrPct 16.60%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.26%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.24%
MFS International Intrinsic Equity Fund | Class B  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MGIBX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 4.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.75%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 1.74%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 577 [3]
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 850 [3]
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 1,148 [3]
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 1,863 [3]
Expense Example, No Redemption, 1 Year oef_ExpenseExampleNoRedemptionYear01 177 [3]
Expense Example, No Redemption, 3 Years oef_ExpenseExampleNoRedemptionYear03 550 [3]
Expense Example, No Redemption, 5 Years oef_ExpenseExampleNoRedemptionYear05 948 [3]
Expense Example, No Redemption, 10 Years oef_ExpenseExampleNoRedemptionYear10 $ 1,863 [3]
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 27.79%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.15%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.19%
MFS International Intrinsic Equity Fund | Class C  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MGICX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.75%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 1.74%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 277 [3]
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 550 [3]
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 948 [3]
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 1,863 [3]
Expense Example, No Redemption, 1 Year oef_ExpenseExampleNoRedemptionYear01 177 [3]
Expense Example, No Redemption, 3 Years oef_ExpenseExampleNoRedemptionYear03 550 [3]
Expense Example, No Redemption, 5 Years oef_ExpenseExampleNoRedemptionYear05 948 [3]
Expense Example, No Redemption, 10 Years oef_ExpenseExampleNoRedemptionYear10 $ 1,863 [3]
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 30.82%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.42%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.18%
MFS International Intrinsic Equity Fund | Class I  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINIX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.75%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.74%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 76
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 239
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 416
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 929
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 33.11%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.48%
Average Annual Return, Percent oef_AvgAnnlRtrPct 10.12%
MFS International Intrinsic Equity Fund | Class R1  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINRX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.75%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 1.74%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 177
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 550
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 948
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 2,062
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 31.80%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.42%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.02%
MFS International Intrinsic Equity Fund | Class R2  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINFX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.25%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 1.24%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 126
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 396
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 685
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,510
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 32.49%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.95%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.57%
MFS International Intrinsic Equity Fund | Class R3  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINGX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.00%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.99%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 101
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 317
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 551
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,224
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 32.77%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.21%
Average Annual Return, Percent oef_AvgAnnlRtrPct 9.84%
MFS International Intrinsic Equity Fund | Class R4  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINHX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.11%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.75%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.74%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 76
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 239
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 416
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 929
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 33.16%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.48%
Average Annual Return, Percent oef_AvgAnnlRtrPct 10.12%
MFS International Intrinsic Equity Fund | Class R6  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol MINJX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) oef_MaximumDeferredSalesChargeOverOfferingPrice 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.64%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.01%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.65%
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets (0.01%) [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.64%
Fee Waiver or Reimbursement over Assets, Date of Termination oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination September 30, 2027
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 65
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 207
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 361
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 809
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Returns Before Taxes
Average Annual Return, Percent oef_AvgAnnlRtrPct 33.29%
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.60%
Average Annual Return, Percent oef_AvgAnnlRtrPct 10.24%
[1] This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase.
[2] Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least September 30, 2027.
[3] Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years.