Prospectus: Series [Axis] Series S000034476 Member Eaton Vance Parametric Structured Absolute Return Fund Eaton Vance Parametric Structured Absolute Return Fund. S000033949 Member Eaton Vance Multi-Strategy All Market Fund Eaton Vance Multi-Strategy All Market Fund. Risk/Return: Risk/Return [Heading] Objective [Heading] Objective, Primary [Text Block] Expense [Heading] Expense Narrative [Text Block] Shareholder Fees Caption [Text] Shareholder Fees [Table] Annual Fund Operating Expenses [Table] Expense Example [Heading] Expense Example Narrative [Text Block] Expense Example by, Year, Caption [Text] Expense Example, With Redemption [Table] Expense Example, No Redemption, By Year, Caption [Text] Expense Example, No Redemption [Table] Portfolio Turnover [Heading] Portfolio Turnover [Text Block] Strategy [Heading] Strategy Narrative [Text Block] Risk [Heading] Risk Narrative [Text Block] Bar Chart and Performance Table [Heading] Performance Narrative [Text Block] Share Class [Axis] Share Classes C000105970 Member Class I Class I shares Class I, Eaton Vance Parametric Structured Absolute Return Fund. Shareholder Fees Shareholder Fees: Shareholder Fees Column [Text] C000104668 Member Class A Class A shares Class A, Eaton Vance Multi-Strategy All Market Fund. C000104757 Member Class C Class C shares Class C, Eaton Vance Multi-Strategy All Market Fund. C000104670 Member Class I Class I shares Class I, Eaton Vance Multi-Strategy All Market Fund. Annual Fund Operating Expenses Operating Expenses: Operating Expenses Caption [Text] Operating Expenses Column [Text] Management Fees Management Fees (as a percentage of Assets) Distribution and Service (12b-1) Fees Distribution and Service (12b-1) Fees Other Expenses (estimated) Other Expenses Other Expenses (as a percentage of Assets): Expenses (as a percentage of Assets) Total Expenses Total Annual Fund Operating Expenses Expense Reimbursement Fee Waiver or Reimbursement Fee Waiver or Reimbursement Total Annual Fund Operating Expenses After Expense Reimbursement Net Expenses Net Expenses (as a percentage of Assets) Acquired Fund Fees and Expenses (estimated) Acquired Fund Fees and Expenses Example. Expense Example: Expense Example, By Year, Column [Text] 1 Year 1 Year Expense Example, with Redemption, 1 Year 3 Years 3 Years Expense Example, with Redemption, 3 Years Expense Example, No Redemption Expense Example, No Redemption: Expense Example, No Redemption, By Year, Column [Text] 1 Year 1 Year Expense Example, No Redemption, 1 Year 3 Years 3 Years Expense Example, No Redemption, 3 Years Document Type Document Period End Date Registrant Name Central Index Key Amendment Flag Trading Symbol Document Creation Date Document Effective Date Prospectus Date Fund Fees And Expenses Abstract Fees and Expenses of the Fund Fund Fees And Expenses. Expense Breakpoint Discounts Abstract Expense Breakpoint Discounts Expense Breakpoint Discounts. Expense Breakpoint Discounts [Text] Expense Breakpoint, Minimum Investment Required [Amount] Fee Waiver or Reimbursement over Assets, Date of Termination Portfolio Turnover Alt Abstract Portfolio Turnover Portfolio Turnover Alt. Strategy Portfolio Concentration [Text] Risk Nondiversified Status [Text] Risk Lose Money [Text] Risk Not Insured Depository Institution [Text] Fund Past Performance Abstract Performance Fund Past Performance. Performance One Year or Less [Text] Maximum Cumulative Sales Charge (as a percentage of Offering Price) Maximum Sales Charge (Load) (as a percentage of offering price) Maximum Deferred Sales Charge (as a percentage) Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption)