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Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Bond Fund May 1, 2013
Objective [Heading] rr_ObjectiveHeading Investment Objective.
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks current income,
Objective, Secondary [Text Block] rr_ObjectiveSecondaryTextBlock

with preservation of shareholders' capital a secondary objective.

Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund.
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

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.

Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment) N/A
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
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 (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 28.89% of the average value of its portfolio.

Portfolio Turnover, Rate rr_PortfolioTurnoverRate 28.89%
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: (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.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption Although your actual costs may be higher or lower, your cost based on these assumptions would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies.
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

The Fund invests primarily in publicly-traded, investment-grade debt securities.


•  At least 80% of the Fund's assets are invested in investment grade bonds issued by U.S. corporations or by the U.S. Government or its agencies, such as bonds, notes, debentures, zero coupon securities and mortgage-backed securities. Bonds are debt instruments that can be issued by the federal government, government agencies and subdivisions, states, cities, corporations and other institutions.


•  It is possible that certain corporate bonds in the Fund's portfolio can be below investment grade, commonly referred to as "junk bonds."


•  The Adviser evaluates each security to be purchased and selects securities based in part on interest income anticipated to be generated.


•  The Fund may invest in foreign securities.

Risk [Heading] rr_RiskHeading Principal Investment Risks.
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

An investment in the Fund is subject to the following risks which are described in more detail in the Prospectus.


•  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.


•  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.


•  Mortgage risk: The duration of mortgage-related securities tends to be inversely related to changes in interest rates. As interest rates rise, the duration of mortgage-related securities extends and as interest rates fall, mortgage-related securities are prepaid at a faster rate. Because of interest rate changes, it is not possible to predict the realized yield or average life of a mortgage-backed security. Mortgage-backed securities issued by private corporations generally have more credit risk than securities issued by U.S. Government agencies.


•  Zero Coupon risk: Zero coupon securities and discount notes do not pay interest prior to maturity and therefore may be more difficult to resell during periods of interest rate changes. The market value of debt securities declines as interest rates rise; therefore the Fund will lose value if it sells zero coupon securities prior to their maturity date. The longer the remaining term to maturity, the greater impact interest rate changes will have on the value of the security.


•  Fixed Income risk: The value of your investment will go up or down depending on movements in the bond markets. The Fund's investment results may differ from the results of a comparable bond market and from the results of other funds that invest in the same types of securities. Mortgage-backed securities or certificates are subject to prepayment or extension risk when interest rates fall or rise, respectively. The prices of debt securities may be subject to significant volatility. Fixed income securities have an inverse relationship to interest rates, such that as interest rates rise, bond values decrease. During economic uncertainty, the value of corporate debt securities may decline relative to the value of U.S. government debt securities. Debt obligations are subject to the risk that issuers may not be able to pay off the principal and interest when due. Non-investment grade debt obligations, known as "junk bonds", have a higher risk of default and tend to be less liquid than higher-rated securities. Adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity to pay interest and repay principal for debt in the junk bond category than in higher-rated categories.


•  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.

Risk Lose Money [Text] rr_RiskLoseMoney An investment in the Fund could decline in value, and you could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance/Annual Return.
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

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, five, and ten years 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.

Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table below show the annual return and average annual returns of the Fund.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-468-3785
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress http://www.mutualofamerica.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture A fund's past performance does not necessarily indicate how it will perform in the future.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Best and Worst Performing Quarters


   

Quarter/Year

 

Total Return

 

Best

 

Second quarter 2009

   

5.92

%

 

Worst

 

Second quarter 2004

   

(2.37

)%

 
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 5.92%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2004
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (2.37%)
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (Index reflects no deduction of any charges against the assets)
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns (for periods ended December 31, 2012)
Barclay's Capital Aggregate Bond Index (Index reflects no deduction of any charges against the assets)
  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 4.21%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 5.95%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.18%
Bond Fund Class
  
Risk/Return: rr_RiskReturnAbstract  
Management Fees rr_ManagementFeesOverAssets 0.39%
Other Expenses rr_OtherExpensesOverAssets 0.15%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.54%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 55
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 174
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 306
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 696
Annual Return 2003 rr_AnnualReturn2003 6.73%
Annual Return 2004 rr_AnnualReturn2004 4.61%
Annual Return 2005 rr_AnnualReturn2005 1.79%
Annual Return 2006 rr_AnnualReturn2006 4.79%
Annual Return 2007 rr_AnnualReturn2007 5.90%
Annual Return 2008 rr_AnnualReturn2008 (1.75%)
Annual Return 2009 rr_AnnualReturn2009 14.61%
Annual Return 2010 rr_AnnualReturn2010 7.29%
Annual Return 2011 rr_AnnualReturn2011 7.30%
Annual Return 2012 rr_AnnualReturn2012 5.79%
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 5.79%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 6.52%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.66%