3.20.1 html 107 163 1 true 76 0 false 2 false false R1.htm 000000 - Document - Document and Entity Information {Elements} Sheet http://www.mutualofamerica.com/role/DocumentDocumentandEntityInformationElements Document and Entity Information 1 false true R2.htm 000011 - Document - Risk/Return Summary {Unlabeled} - Equity Index Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledEquityIndexFund Risk/Return Summary- Equity Index Fund 2 false false R9.htm 000019 - Disclosure - Risk/Return Detail Data {Elements} - Equity Index Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsEquityIndexFund Risk/Return Detail Data- Equity Index Fund 3 false true R10.htm 000021 - Document - Risk/Return Summary {Unlabeled} - All America Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledAllAmericaFund Risk/Return Summary- All America Fund 4 false false R17.htm 000029 - Disclosure - Risk/Return Detail Data {Elements} - All America Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsAllAmericaFund Risk/Return Detail Data- All America Fund 5 false true R18.htm 000031 - Document - Risk/Return Summary {Unlabeled} - Small Cap Value Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledSmallCapValueFund Risk/Return Summary- Small Cap Value Fund 6 false false R25.htm 000039 - Disclosure - Risk/Return Detail Data {Elements} - Small Cap Value Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsSmallCapValueFund Risk/Return Detail Data- Small Cap Value Fund 7 false true R26.htm 000041 - Document - Risk/Return Summary {Unlabeled} - Small Cap Growth Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledSmallCapGrowthFund Risk/Return Summary- Small Cap Growth Fund 8 false false R33.htm 000049 - Disclosure - Risk/Return Detail Data {Elements} - Small Cap Growth Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsSmallCapGrowthFund Risk/Return Detail Data- Small Cap Growth Fund 9 false true R34.htm 000051 - Document - Risk/Return Summary {Unlabeled} - Small Cap Equity Index Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledSmallCapEquityIndexFund Risk/Return Summary- Small Cap Equity Index Fund 10 false false R41.htm 000059 - Disclosure - Risk/Return Detail Data {Elements} - Small Cap Equity Index Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsSmallCapEquityIndexFund Risk/Return Detail Data- Small Cap Equity Index Fund 11 false true R42.htm 000061 - Document - Risk/Return Summary {Unlabeled} - Mid Cap Value Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledMidCapValueFund Risk/Return Summary- Mid Cap Value Fund 12 false false R49.htm 000069 - Disclosure - Risk/Return Detail Data {Elements} - Mid Cap Value Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsMidCapValueFund Risk/Return Detail Data- Mid Cap Value Fund 13 false true R50.htm 000071 - Document - Risk/Return Summary {Unlabeled} - Mid-Cap Equity Index Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledMid-CapEquityIndexFund Risk/Return Summary- Mid-Cap Equity Index Fund 14 false false R57.htm 000079 - Disclosure - Risk/Return Detail Data {Elements} - Mid-Cap Equity Index Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsMid-CapEquityIndexFund Risk/Return Detail Data- Mid-Cap Equity Index Fund 15 false true R58.htm 000081 - Document - Risk/Return Summary {Unlabeled} - Composite Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledCompositeFund Risk/Return Summary- Composite Fund 16 false false R65.htm 000089 - Disclosure - Risk/Return Detail Data {Elements} - Composite Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsCompositeFund Risk/Return Detail Data- Composite Fund 17 false true R66.htm 000091 - Document - Risk/Return Summary {Unlabeled} - International Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledInternationalFund Risk/Return Summary- International Fund 18 false false R73.htm 000099 - Disclosure - Risk/Return Detail Data {Elements} - International Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsInternationalFund Risk/Return Detail Data- International Fund 19 false true R74.htm 000101 - Document - Risk/Return Summary {Unlabeled} - Catholic Values Index Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledCatholicValuesIndexFund Risk/Return Summary- Catholic Values Index Fund 20 false false R79.htm 000109 - Disclosure - Risk/Return Detail Data {Elements} - Catholic Values Index Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsCatholicValuesIndexFund Risk/Return Detail Data- Catholic Values Index Fund 21 false true R80.htm 000111 - Document - Risk/Return Summary {Unlabeled} - Money Market Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledMoneyMarketFund Risk/Return Summary- Money Market Fund 22 false false R87.htm 000119 - Disclosure - Risk/Return Detail Data {Elements} - Money Market Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsMoneyMarketFund Risk/Return Detail Data- Money Market Fund 23 false true R88.htm 000121 - Document - Risk/Return Summary {Unlabeled} - Mid-Term Bond Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledMid-TermBondFund Risk/Return Summary- Mid-Term Bond Fund 24 false false R95.htm 000129 - Disclosure - Risk/Return Detail Data {Elements} - Mid-Term Bond Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsMid-TermBondFund Risk/Return Detail Data- Mid-Term Bond Fund 25 false true R96.htm 000131 - Document - Risk/Return Summary {Unlabeled} - Bond Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledBondFund Risk/Return Summary- Bond Fund 26 false false R103.htm 000139 - Disclosure - Risk/Return Detail Data {Elements} - Bond Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsBondFund Risk/Return Detail Data- Bond Fund 27 false true R104.htm 000141 - Document - Risk/Return Summary {Unlabeled} - Retirement Income Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledRetirementIncomeFund Risk/Return Summary- Retirement Income Fund 28 false false R111.htm 000149 - Disclosure - Risk/Return Detail Data {Elements} - Retirement Income Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsRetirementIncomeFund Risk/Return Detail Data- Retirement Income Fund 29 false true R112.htm 000151 - Document - Risk/Return Summary {Unlabeled} - 2010 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2010RetirementFund Risk/Return Summary- 2010 Retirement Fund 30 false false R119.htm 000159 - Disclosure - Risk/Return Detail Data {Elements} - 2010 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2010RetirementFund Risk/Return Detail Data- 2010 Retirement Fund 31 false true R120.htm 000161 - Document - Risk/Return Summary {Unlabeled} - 2015 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2015RetirementFund Risk/Return Summary- 2015 Retirement Fund 32 false false R127.htm 000169 - Disclosure - Risk/Return Detail Data {Elements} - 2015 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2015RetirementFund Risk/Return Detail Data- 2015 Retirement Fund 33 false true R128.htm 000171 - Document - Risk/Return Summary {Unlabeled} - 2020 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2020RetirementFund Risk/Return Summary- 2020 Retirement Fund 34 false false R135.htm 000179 - Disclosure - Risk/Return Detail Data {Elements} - 2020 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2020RetirementFund Risk/Return Detail Data- 2020 Retirement Fund 35 false true R136.htm 000181 - Document - Risk/Return Summary {Unlabeled} - 2025 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2025RetirementFund Risk/Return Summary- 2025 Retirement Fund 36 false false R143.htm 000189 - Disclosure - Risk/Return Detail Data {Elements} - 2025 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2025RetirementFund Risk/Return Detail Data- 2025 Retirement Fund 37 false true R144.htm 000191 - Document - Risk/Return Summary {Unlabeled} - 2030 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2030RetirementFund Risk/Return Summary- 2030 Retirement Fund 38 false false R151.htm 000199 - Disclosure - Risk/Return Detail Data {Elements} - 2030 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2030RetirementFund Risk/Return Detail Data- 2030 Retirement Fund 39 false true R152.htm 000201 - Document - Risk/Return Summary {Unlabeled} - 2035 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2035RetirementFund Risk/Return Summary- 2035 Retirement Fund 40 false false R159.htm 000209 - Disclosure - Risk/Return Detail Data {Elements} - 2035 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2035RetirementFund Risk/Return Detail Data- 2035 Retirement Fund 41 false true R160.htm 000211 - Document - Risk/Return Summary {Unlabeled} - 2040 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2040RetirementFund Risk/Return Summary- 2040 Retirement Fund 42 false false R167.htm 000219 - Disclosure - Risk/Return Detail Data {Elements} - 2040 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2040RetirementFund Risk/Return Detail Data- 2040 Retirement Fund 43 false true R168.htm 000221 - Document - Risk/Return Summary {Unlabeled} - 2045 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2045RetirementFund Risk/Return Summary- 2045 Retirement Fund 44 false false R175.htm 000229 - Disclosure - Risk/Return Detail Data {Elements} - 2045 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2045RetirementFund Risk/Return Detail Data- 2045 Retirement Fund 45 false true R176.htm 000231 - Document - Risk/Return Summary {Unlabeled} - 2050 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2050RetirementFund Risk/Return Summary- 2050 Retirement Fund 46 false false R183.htm 000239 - Disclosure - Risk/Return Detail Data {Elements} - 2050 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2050RetirementFund Risk/Return Detail Data- 2050 Retirement Fund 47 false true R184.htm 000241 - Document - Risk/Return Summary {Unlabeled} - 2055 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2055RetirementFund Risk/Return Summary- 2055 Retirement Fund 48 false false R191.htm 000249 - Disclosure - Risk/Return Detail Data {Elements} - 2055 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2055RetirementFund Risk/Return Detail Data- 2055 Retirement Fund 49 false true R192.htm 000251 - Document - Risk/Return Summary {Unlabeled} - 2060 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2060RetirementFund Risk/Return Summary- 2060 Retirement Fund 50 false false R199.htm 000259 - Disclosure - Risk/Return Detail Data {Elements} - 2060 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2060RetirementFund Risk/Return Detail Data- 2060 Retirement Fund 51 false true R200.htm 000261 - Document - Risk/Return Summary {Unlabeled} - 2065 Retirement Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeled2065RetirementFund Risk/Return Summary- 2065 Retirement Fund 52 false false R205.htm 000269 - Disclosure - Risk/Return Detail Data {Elements} - 2065 Retirement Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElements2065RetirementFund Risk/Return Detail Data- 2065 Retirement Fund 53 false true R206.htm 000271 - Document - Risk/Return Summary {Unlabeled} - Conservative Allocation Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledConservativeAllocationFund Risk/Return Summary- Conservative Allocation Fund 54 false false R213.htm 000279 - Disclosure - Risk/Return Detail Data {Elements} - Conservative Allocation Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsConservativeAllocationFund Risk/Return Detail Data- Conservative Allocation Fund 55 false true R214.htm 000281 - Document - Risk/Return Summary {Unlabeled} - Moderate Allocation Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledModerateAllocationFund Risk/Return Summary- Moderate Allocation Fund 56 false false R221.htm 000289 - Disclosure - Risk/Return Detail Data {Elements} - Moderate Allocation Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsModerateAllocationFund Risk/Return Detail Data- Moderate Allocation Fund 57 false true R222.htm 000291 - Document - Risk/Return Summary {Unlabeled} - Aggressive Allocation Fund Sheet http://www.mutualofamerica.com/role/DocumentRiskReturnSummaryUnlabeledAggressiveAllocationFund Risk/Return Summary- Aggressive Allocation Fund 58 false false R229.htm 000299 - Disclosure - Risk/Return Detail Data {Elements} - Aggressive Allocation Fund Sheet http://www.mutualofamerica.com/role/DisclosureRiskReturnDetailDataElementsAggressiveAllocationFund Risk/Return Detail Data- Aggressive Allocation Fund 59 false false R230.htm 040000 - Disclosure - Risk/Return Detail Data {Elements} Sheet http://xbrl.sec.gov/rr/role/RiskReturnDetailData Risk/Return Detail Data 60 false false All Reports Book All Reports maic-20200428.xml maic-20200428.xsd maic-20200428_cal.xml maic-20200428_def.xml maic-20200428_lab.xml maic-20200428_pre.xml g817400g817400g08r00.jpg BarChart1.png BarChart2.png BarChart3.png BarChart4.png BarChart5.png BarChart6.png BarChart7.png BarChart8.png BarChart9.png BarChart10.png BarChart11.png BarChart12.png BarChart13.png BarChart14.png BarChart15.png BarChart16.png BarChart17.png BarChart18.png BarChart19.png BarChart20.png BarChart21.png BarChart22.png BarChart23.png BarChart24.png BarChart25.png BarChart26.png BarChart27.png http://xbrl.sec.gov/dei/2018-01-31 http://xbrl.sec.gov/rr/2018-01-31 true true