Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - 2013 Omnibus Equity Incentive Plan - Award Limitations - Additional Information (Detail)

v2.4.1.9
Stock-Based Compensation Plans - 2013 Omnibus Equity Incentive Plan - Award Limitations - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Incentive_Plan
2013 Omnibus Equity Incentive Plan [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of active equity plans 1mmi_NumberOfActiveEquityPlans
/ us-gaap_PlanNameAxis
= mmi_TwoThousandAndThirteenOmnibusEquityAwardPlanMember
Common stock shares reserved for issuance of awards 5,500,000us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_PlanNameAxis
= mmi_TwoThousandAndThirteenOmnibusEquityAwardPlanMember
Common stock shares available for grant 3,297,829us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= mmi_TwoThousandAndThirteenOmnibusEquityAwardPlanMember
Common stock available for future issuance authorized annual percentage increase 3.00%mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfAvailableShareIncrease
/ us-gaap_PlanNameAxis
= mmi_TwoThousandAndThirteenOmnibusEquityAwardPlanMember
Increase of common stock share reserve approved 1,100,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardAvailableShareIncrease
/ us-gaap_PlanNameAxis
= mmi_TwoThousandAndThirteenOmnibusEquityAwardPlanMember
Options & SARs [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 500,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= mmi_OptionsAndStockAppreciationRightsMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Options & SARs [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 1,000,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= mmi_OptionsAndStockAppreciationRightsMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Restricted Stock and RSUs [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 500,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= mmi_RestrictedStockAndRsuMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Restricted Stock and RSUs [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 1,000,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= mmi_RestrictedStockAndRsuMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Performance Shares [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of award limitation, performance units or performance shares 1mmi_NumberOfAwardLimitationPerformanceUnitsOrPerformanceShares
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
Performance Shares [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 500,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Grant date fair value limitations to awards granted under the 2013 Plan 2mmi_PerformanceUnitsAndPerformanceSharesGrantsInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Performance Shares [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share limitations to awards granted under the 2013 Plan 1,000,000mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesLimitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Grant date fair value limitations to awards granted under the 2013 Plan 5mmi_PerformanceUnitsAndPerformanceSharesGrantsInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember