2.2.0.25truefalse061044 - Document - Risk/Return Summary {Unlabeled} (International Fund)falsefalsetrue1falsefalsetruefalse{dei_DocumentInformationDocumentAxis} : SummaryS000017204 Member {dei_LegalEntityAxis} : S000017204 Member 5/1/2011 - 5/1/2011 eol_0001104659-11-023833_STD_1_20110501_0_396770x-9996523_396840x-9990954http://www.sec.gov/CIK0000795259duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseck0000795259_SummaryS000017204Memberdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_SummaryS000017204Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseck0000795259_S000017204Memberdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberpureStandardhttp://www.xbrl.org/2003/instancepure01false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.mutualofamerica.com/role/riskreturn_s000017204member1falsefalsefalse00International Fund (Prospectus Summary) | International FundInternational Fund (Prospectus Summary) | International Fundfalsefalsefalsefalsefalse1falsefalsetruefalse{dei_DocumentInformationDocumentAxis} : SummaryS000017204 Member {dei_LegalEntityAxis} : S000017204 Member 5/1/2011 - 5/1/2011 eol_0001104659-11-023833_STD_1_20110501_0_396770x-9996523_396840x-9990954http://www.sec.gov/CIK0000795259duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseck0000795259_SummaryS000017204Memberdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_SummaryS000017204Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseck0000795259_S000017204Memberdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberpureStandardhttp://www.xbrl.org/2003/instancepure0OthernaNo definition available.No authoritative reference available.falsefalseInternational Fund (Prospectus Summary) | International Fund3false0rr_RiskReturnHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00International Fund May 1, 2011falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicatedReference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 falsefalseRisk/Return, Heading4false0rr_ObjectiveHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Investment Objective.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a falsefalseInvestment Objective, Heading5false0rr_ObjectivePrimaryTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>The Fund seeks capital appreciation.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a falsefalseinvestment Objective, Primary6false0rr_ExpenseHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Fees and Expenses of the Fund.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Summary Fee Table Includes the following information, in plain English under rule 421(d) under the Securities Act, after Item 2 Fees and expenses of the Fund This table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Shareholder Fees (fees paid directly from your investment) Example 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 then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be You would pay the following expenses if you did not redeem your shares The Example does not reflect sales charges (loads) on reinvested dividends [and other distributions]. If these sales charges (loads) were included, your costs would be higher. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs. These 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 __% of the average value of its whole portfolio. Instructions. A.3.instructions.6 New Funds. For purposes of this Item, a "New Fund" is a Fund that does not include in Form N-1A financial statements reporting operating results or that includes financial statements for the Fund's initial fiscal year reporting operating results for a period of 6 months or less. The following Instructions apply to New Funds.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph d -Subsection instructions falsefalseExpense, Heading7false0rr_ExpenseNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>The table below describes the fees and expenses you may pay if you buy and hold Fund shares. The expenses shown do not include Separate Account expenses which would increase costs if included.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown.The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph b -Subsection instructions falsefalseExpense, Narrative8false0rr_ShareholderFeesCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Shareholder Fees (fees paid directly from your investment) N/A falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringShareholder Fees (fees paid directly from your investment).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subsection table falsefalseShareholder Fees, Caption9false0rr_OperatingExpensesCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringAnnual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investment)Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 7 -Subsection table falsefalseOperating Expenses, Caption10false0rr_AnnualFundOperatingExpensesTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="display:none">~ http://www.mutualofamerica.com/role/OperatingExpensesData_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsefalse<div style="display:none">~ http://www.mutualofamerica.com/role/OperatingExpensesData_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsehttp://www.mutualofamerica.com/role/OperatingExpensesData_S000017204Memberfalsefalse061045 - Schedule - Annual Fund Operating Expensestruefalsefalse1falseColumnperiodPeriod*Columndei_LegalEntityAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseInternational Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberfalsefalseInternational Fund Classrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_C000047659Memberrr_ProspectusShareClassAxisexplicitMemberInternational FundInternational Fund Classiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$1falseRowprimaryElement*3false0rr_ManagementFeesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00080.0008falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureManagement Fees include investment advisory fees (including any fees based on the Fund's performance), any other management fees payable to the investment adviser or its affiliates, and administrative fees payable to the investment adviser or its affiliates that are not included as "Other Expenses."Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph a -Subsection instructions falsefalseManagement Fees0rr_ManagementFeesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00080.0008falsefalsefalsetruefalseOthernanafalsefalseManagement Fees2falseRowprimaryElement*4false0rr_OtherExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00160.0016falsefalsefalsetruefalseOtherrr:NonNegativePure4Typepure"Other Expenses" include all expenses not otherwise disclosed in the table that are deducted from the Fund's assets or charged to all shareholder accounts. The amount of expenses deducted from the Fund's assets are the amounts shown as expenses in the Fund's statement of operations (including increases resulting from complying with paragraph 2(g) of rule 6-07 of Regulation S-X [17 CFR 210.6-07]). "Other Expenses" do not include extraordinary expenses as determined under generally accepted accounting principles (see Accounting Principles Board Opinion No. 30). If extraordinary expenses were incurred that materially affected the Fund's "Other Expenses," disclose in a footnote to the table what "Other Expenses" would have been had the extraordinary expenses been included.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph c -Clause i -Subsection instructions falsefalseOther Expenses0rr_OtherExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00160.0016falsefalsefalsetruefalseOthernanafalsefalseOther Expenses3falseRowprimaryElement*5false0rr_AcquiredFundFeesAndExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00230.0023falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 11 -Subsection table falsefalseAcquired Fund Fees & Expenses0rr_AcquiredFundFeesAndExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00230.0023falsefalsefalsetruefalseOthernanafalsefalseAcquired Fund Fees & Expenses4falseRowprimaryElement*6false0rr_ExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00470.0047falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses. If the Fund is a Feeder Fund, reflect the aggregate expenses of the Feeder Fund and the Master Fund in a single fee table using the captions provided. In a footnote to the fee table, state that the table and Example reflect the expenses of both the Feeder and Master Funds. If the prospectus offers more than one Class of a Multiple Class Fund or more than one Feeder Fund that invests in the same Master Fund, provide a separate response for each Class or Feeder Fund. Base the percentages of "Annual Fund Operating Expenses" on amounts incurred during the Fund's most recent fiscal year, but include in expenses amounts that would have been incurred absent expense reimbursement or fee waiver arrangements. If the Fund has changed its fiscal year and, as a result, the most recent fiscal year is less than three months, use the fiscal year prior to the most recent fiscal year as the basis for determining "Annual Fund Operating Expenses."Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph d -Subsection instructions falsefalseTotal Annual Fund Operating Expenses0rr_ExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00470.0047falsefalsefalsetruefalseOthernanafalsefalseTotal Annual Fund Operating Expenses14Annual Fund Operating Expenses UnKnownUnKnownUnKnownUnKnownfalsetrueColumnperiodPeriod*Columndei_LegalEntityAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to OperatingExpensesData.No authoritative reference available.falsefalseAnnual Fund Operating Expenses [Table]11false0rr_ExpenseExampleHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Example.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringHeading for Expense Example.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subsection instructions falsefalseExpense Example, Heading12false0rr_ExpenseExampleNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>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: (a) that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods, (b) a 5% return each year and (c) operating expenses remain the same. The expenses shown do not include Separate Account expenses which would increase costs if included.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThe Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 1 -Subsection example falsefalseExpense Example, Narrative13false0rr_ExpenseExampleByYearCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Although your actual costs may be higher or lower, your cost based on these assumptions would be: falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example, By Year, Caption14false0rr_ExpenseExampleWithRedemptionTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="display:none">~ http://www.mutualofamerica.com/role/ExpenseExample_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsefalse<div style="display:none">~ http://www.mutualofamerica.com/role/ExpenseExample_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>truehttp://www.mutualofamerica.com/role/ExpenseExample_S000017204Memberfalsefalse061046 - Schedule - Expense Example {Transposed}truefalsefalse1falseColumnprimaryElement*3false0rr_ExpenseExampleYear01rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue4848falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subsection instructions falsefalseExpense Example, With Redemption, 1 YearfalseUSDfalsefalse$2falseColumnprimaryElement*4false0rr_ExpenseExampleYear03rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue152152falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example, With Redemption, 3 YearsfalseUSDfalsefalse$3falseColumnprimaryElement*5false0rr_ExpenseExampleYear05rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue266266falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example, With Redemption, 5 YearsfalseUSDfalsefalse$4falseColumnprimaryElement*6false0rr_ExpenseExampleYear10rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue606606falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example, With Redemption, 10 YearsfalseUSDfalsefalse$1falseRowperiodPeriod*Rowdei_LegalEntityAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseInternational Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberfalsefalseInternational Fund Classrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_C000047659Memberrr_ProspectusShareClassAxisexplicitMemberInternational FundInternational Fund Classiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue4848falsefalsefalsetruefalse2truefalsetrue152152falsefalsefalsetruefalse3truefalsetrue266266falsefalsefalsetruefalse4truefalsetrue606606falsefalsefalsetruefalseOthernanafalsefalseInternational Fund International Fund Class41Expense Example (USD $)UnKnownUnKnownUnKnownUnKnownfalsetrueColumnprimaryElement*RowperiodPeriod*Rowdei_LegalEntityAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to ExpenseExample.No authoritative reference available.falsefalseExpense Example, With Redemption [Table]15false0rr_PortfolioTurnoverHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Portfolio Turnover.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 5 -Subsection instructions falsefalsePortfolio Turnover, Heading16false0rr_PortfolioTurnoverTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>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 result in higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund's performance. During the Fund's most recently completed fiscal year, the Fund's portfolio turnover rate was 9.17% of the average value of its portfolio.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subsection example falsefalsePortfolio Turnover17false0rr_StrategyHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Principal Investment Strategies.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a falsefalseInvestment Strategy, Heading18false0rr_StrategyNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>The Fund invests, directly and/or indirectly, mainly in stocks of companies located outside of the United States that reflect or are contained in the Morgan Stanley Capital International, Inc. Europe, Australasia, and Far East Index (the "MSCI EAFE Index"). At present, the Fund expects to invest substantially all of its assets in exchange traded funds.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a falsefalseInvestment Strategy, Narrative19false0rr_RiskHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Principal Investment Risks.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNarrative Risk Disclosure.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 1 -Subsection b falsefalseRisk, Heading20false0rr_RiskNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>An investment in the Fund is subject to the following risks which are described in more detail in the Prospectus. &#x2022; General risk: The Fund may not achieve its investment objective. An investment in the Fund could decline in value, and you could lose money by investing in the Fund. &#x2022; Company risk: The price of the stock of a particular company can vary based on a variety of factors, such as the company's financial performance, changes in management and product trends, and the potential for takeover and acquisition. The prices of equity securities of smaller companies may fluctuate more than for more established companies. The equity securities of smaller companies may not be traded as often as for larger companies, therefore it may be difficult to trade securities at a desirable price. Investments in companies with small market capitalizations generally offer greater opportunities for appreciation, but are associated with more risks than for established companies. &#x2022; Market risk: The risk that prices of securities will go down because of the interplay of market forces may affect a single issuer, industry or sector of the economy or may affect the market as a whole. &#x2022; Index risk: The Fund's investment performance may not precisely duplicate the performance of the index. The Fund may rebalance the portfolio to account for changes in the composition of the index or in the valuations of the stocks within the index. &#x2022; Liquidity risk: The Fund's investments in illiquid securities, investments that are difficult to purchase or sell, may reduce returns if the Fund is unable to sell at an advantageous time or price. Foreign securities, derivatives or securities with substantial market and/or credit risk and securities that trade over-the-counter tend to have the greatest exposure to liquidity risk. &#x2022; Foreign Investment risk: Foreign markets are subject to the risk of change in currency or exchange rates, economic and political trends in foreign countries, less liquidity, more volatility, more difficulty in enforcing contractual obligations, higher transaction costs and less government supervision and other reporting regulations and requirements than domestic markets. &#x2022; ETF risk: ETFs generally invest substantially all of their assets in securities and are traded on stock exchanges. Their net asset values may differ from the prices of the ETF shares offered on the exchanges. &#x2022; Depositary Receipts Risk: The underlying ETF may invest in securities of foreign issuers in the form of depositary receipts, some of which are not obligated to disclose material information. &#x2022; Inactive Market Risk: ETF shares are listed exchanges for which there can be no assurance that it will maintain the listing. Also there is no assurance that an active trading market will develop, creating illiquidity and resulting in price volatility. Also trading on these exchanges may be halted because of market conditions or extraordinary market volatility. &#x2022; Investment Company Risk: The cost of investing in the Fund is higher because in addition to the Fund's direct fees and expenses, it also indirectly bears fees and expenses charged by the underlying ETFs. The underlying ETFs may change their investment objectives or policies without the approval of the Fund, causing the Fund to withdraw its investment at a possibly inopportune time. &#x2022; Leveraging Risk: ETFs may borrow money or otherwise leverage their holdings by investing in collateral from securities loans and by borrowing money to meet redemption requests. This leveraging results in more volatility and a compounding of all other risks. &#x2022; Net Asset Value Risk: The market price of an underlying ETF may be different from its net asset value. &#x2022; Passive Investment Risk: Many ETFs are not actively managed; rather the underlying ETF invests in securities that represent its underlying index, regardless of its investment merit or market trends. Also, an underlying ETF is more susceptible to declines in the market because the underlying ETFs generally do not change their investment strategies to respond to changes in the economy. &#x2022; Tracking Error Risk: Imperfect correlation between the securities of an ETF and those in the index it intends to track, rounding of prices, changes to the indices and regulatory policies may cause the performance of an ETF to not match the performance of its index. &#x2022; Underlying ETF Management Risk: No underlying ETF fully replicates its index; therefore there is a risk that the investment strategy of each underlying ETF may not produce the intended results. &#x2022; Valuation Risk: An underlying ETF may value certain securities at higher prices than the prices at which it can sell them. &#x2022; Stock risk: The value of your investment will go up or down, depending on movements in the stock markets. The investment results may be better or worse than the results for the stock markets taken as a whole, or than the results of other funds that invest in the same types of securities. It may be more difficult for the Fund to sell a small capitalization stock or any stock that trades "over-the-counter", than a larger capitalization stock or stocks that trade on a national or regional stock exchange. &#x2022; International Fund risk: The Fund is subject to the risks of investing in securities that trade in foreign markets, including changes in currency or exchange rates, and economic and political trends in foreign countries. Domestic equities indices could outperform the MSCI EAFE Index for periods of time. The Fund may invest substantially all or a significant portion of its assets in ETFs.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringNarrative Risk Disclosure. A Fund may, in responding to this Item, describe the types of investors for whom the Fund is intended or the types of investment goals that may be consistent with an investment in the Fund.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 1 -Subparagraph i -Clause instruction -Subsection b falsefalseRisk, Narrative21false0rr_BarChartAndPerformanceTableHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Performance/Annual Return.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Bar Chart and Table.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subsection b falsefalseBar Chart and Performance Table, Heading22false0rr_PerformanceNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>The bar chart and table below show the annual return and average annual returns of the Fund. Below the bar chart are the Fund's highest and lowest total returns for any calendar quarter during the period covered by the chart, showing the volatility of the Fund's total returns. The numbers in parentheses are negative, representing a loss of principal. The information indicates some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for one year and the life of the Fund compare to those of a broad-based, unmanaged index for those periods. A fund's past performance does not necessarily indicate how it will perform in the future. The total returns and average annual total returns shown do not include charges against the assets of the Separate Accounts that purchase Fund shares. If these charges were reflected, returns would be less than those shown. Updated performance information is available at no cost online at http://www.mutualofamerica.com or by calling 1-800-468-3785.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringRisk/Return Bar Chart and Table.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subsection b falsefalsePerformance, Narrative23false0rr_BarChartNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>The bar chart and table below show the annual return and average annual returns of the Fund.</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringProvide a brief explanation of how the information illustrates the variability of the Fund's returns (e.g., by stating that the information provides some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance). Provide a statement to the effect that the Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph i -Subsection b falsefalseBar Chart, Narrative24false0rr_BarChartTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="display:none">~ http://www.mutualofamerica.com/role/BarChartData_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsefalseBarChart8.jpg<div style="display:none">~ http://www.mutualofamerica.com/role/BarChartData_S000017204Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsehttp://www.mutualofamerica.com/role/BarChartData_S000017204Memberfalsefalse061047 - Schedule - Annual Total Returnstruefalsefalse1falseColumnperiodPeriod*Columndei_LegalEntityAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseInternational Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberfalsefalseInternational Fund Classrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_C000047659Memberrr_ProspectusShareClassAxisexplicitMemberInternational FundInternational Fund Classiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$1falseRowprimaryElement*10false0rr_AnnualReturn2008rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.4006-0.4006falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalseAnnual Return 20080rr_AnnualReturn2008truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.4006-0.4006falsefalsefalsetruefalseOthernanafalsefalseAnnual Return 20082falseRowprimaryElement*11false0rr_AnnualReturn2009rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.25220.2522falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a -Subsection b falsefalseAnnual Return 20090rr_AnnualReturn2009truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.25220.2522falsefalsefalsetruefalseOthernanafalsefalseAnnual Return 20093falseRowprimaryElement*12false0rr_AnnualReturn2010rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.08320.0832falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalseAnnual Return 20100rr_AnnualReturn2010truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.08320.0832falsefalsefalsetruefalseOthernanafalsefalseAnnual Return 201013Annual Total Returns UnKnownUnKnownUnKnownUnKnownfalsetrueColumnperiodPeriod*Columndei_LegalEntityAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to BarChartData.No authoritative reference available.falsefalseBar Chart [Table]25false0rr_BarChartClosingTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<pre>Best and Worst Performing Quarters Quarter/Year Total Return Best Second quarter 2009 23.90 % Worst Fourth quarter 2008 (19.02)%</pre>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalseBar Chart, Closing26false0rr_AverageAnnualReturnCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Average Annual Total Returns (for periods ended December 31, 2010)falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 5 -Subsection b falsefalseAverage Annual Returns, Caption27false0rr_PerformanceTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="display:none">~ http://www.mutualofamerica.com/role/PerformanceTableData_S000017204Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>falsefalse<div style="display:none">~ http://www.mutualofamerica.com/role/PerformanceTableData_S000017204Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div>truehttp://www.mutualofamerica.com/role/PerformanceTableData_S000017204Memberfalsefalse061048 - Schedule - Average Annual Total Returns {Transposed}truefalsefalse1falseColumnprimaryElement*3false0rr_AverageAnnualReturnLabelrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00International Fund (commenced operations on November 5, 2007)falsefalsefalsetruefalse2falsetruefalse00MSCI EAFE Index (Index reflects no deduction of any charges against the assets)falsefalsefalsetruefalseOtherxbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalseAverage Annual Returns, LabelfalseUSDfalsefalse$2falseColumnprimaryElement*4false0rr_AverageAnnualReturnYear01rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.08320.0832falsefalsefalsetruefalse2truetruetrue0.08210.0821falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalseAverage Annual Returns, 1 YearfalseUSDfalsefalse$3falseColumnprimaryElement*7false0rr_AverageAnnualReturnSinceInceptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue-0.0723-0.0723falsefalsefalsetruefalse2truetruetrue-0.0705-0.0705falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalseAverage Annual Returns, Since InceptionfalseUSDfalsefalse$4falseColumnprimaryElement*8false0rr_AverageAnnualReturnInceptionDaterrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse002007-11-05falsefalsetruetruefalse2falsetruefalse002007-11-05falsefalsetruetruefalseOtherxbrli:dateItemTypedateReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 4 -Subsection b falsefalseAverage Annual Returns, Inception DatefalseUSDfalsefalse$1falseRowperiodPeriod*Rowdei_LegalEntityAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseInternational Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMembertruefalseBefore Taxesrr_PerformanceMeasureAxisrr_PerformanceMeasureDomainrr_PerformanceMeasureAxisexplicitMemberfalsefalseInternational Fund Classrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_C000047659Memberrr_ProspectusShareClassAxisexplicitMemberInternational FundBefore TaxesInternational Fund Classiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00International Fund (commenced operations on November 5, 2007)International Fund (commenced operations on November 5, 2007)falsefalsefalsetruefalse2truetruetrue0.08320.0832falsefalsefalsetruefalse3truetruetrue-0.0723-0.0723falsefalsefalsetruefalse4falsetruefalse002007-11-052007-11-05falsefalsetruetruefalseOthernanafalsefalseInternational Fund Class2falseRowperiodPeriod*Rowdei_LegalEntityAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2011-05-01T00:00:002011-05-01T00:00:00falsefalseInternational Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_S000017204Memberdei_LegalEntityAxisexplicitMemberfalsefalseMSCI EAFE Indexrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldick0000795259_RRINDEX00011Memberrr_PerformanceMeasureAxisexplicitMembertruefalseShare Classesrr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberInternational FundMSCI EAFE IndexShare ClassesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00MSCI EAFE Index (Index reflects no deduction of any charges against the assets)MSCI EAFE Index (Index reflects no deduction of any charges against the assets)falsefalsefalsetruefalse2truetruetrue0.08210.0821falsefalsefalsetruefalse3truetruetrue-0.0705-0.0705falsefalsefalsetruefalse4falsetruefalse002007-11-052007-11-05falsefalsetruetruefalseOthernanafalsefalseMSCI EAFE Index42Average Annual Total Returns International FundUnKnownUnKnownUnKnownUnKnownfalsetrueColumnprimaryElement*RowperiodPeriod*Rowdei_LegalEntityAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to PerformanceTableData.No authoritative reference available.falsefalsePerformance [Table]126Risk/Return Summary (International Fund) (International Fund (Prospectus Summary), International Fund)UnKnownUnKnownUnKnownUnKnownfalsetrue