Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Additional Information (Detail)

v2.4.1.9
Stock-Based Compensation - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 10 Months Ended 12 Months Ended
Dec. 31, 2013
Oct. 31, 2013
Dec. 31, 2013
Dec. 31, 2014
Age
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation charges $ 30,900mmi_StockbasedCompensationInConnectionWithInitialPublicOffering $ 30,886mmi_StockbasedCompensationInConnectionWithInitialPublicOffering $ 30,886mmi_StockbasedCompensationInConnectionWithInitialPublicOffering  
Deferred stock units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
DSU settlement to common stock percentage       20.00%mmi_DeferredStockUnitsSettlementToCommonStockPercentage
/ us-gaap_AwardTypeAxis
= mmi_DeferredStockUnitsMember
DSU settlement into actual stock issued term       5 years
Employee termination age       67mmi_EmployeeTerminationAge
/ us-gaap_AwardTypeAxis
= mmi_DeferredStockUnitsMember
Percentage of deferred stock units settled       100.00%mmi_PercentageOfDeferredStockUnitsSettled
/ us-gaap_AwardTypeAxis
= mmi_DeferredStockUnitsMember
Percentage of shares of deferred stock units released from resale restriction in the event of death or termination after reaching age 67       100.00%mmi_PercentageOfSharesOfDeferredStockUnitsReleasedFromResaleRestriction
/ us-gaap_AwardTypeAxis
= mmi_DeferredStockUnitsMember
Restricted Stock [Member] | Sales Restricted [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Sales restriction lapse percentage for restricted stock       20.00%mmi_RestrictedCommonStockSaleRestrictionLapsePercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= mmi_SalesRestrictedMember
Sales restriction period for restricted stock       5 years
Employee termination age       67mmi_EmployeeTerminationAge
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= mmi_SalesRestrictedMember
Percentage of shares of stock released from resale restriction upon consummation of change of control       100.00%mmi_PercentageOfSharesOfCommonStockReleasedFromResaleRestrictionOnChangeOfControl
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= mmi_SalesRestrictedMember
Percentage of shares of restricted released from resale restriction in the event of death or termination after reaching age 67       100.00%mmi_PercentageOfSharesOfRestrictedReleasedFromResaleRestrictionInEventOfDeathOrTerminationAfterReachingAgeSixtySeven
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= mmi_SalesRestrictedMember