Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - Outstanding Awards Under 2013 Omnibus Equity Incentive Plan (Detail)

v2.4.1.9
Stock-Based Compensation Plans - Outstanding Awards Under 2013 Omnibus Equity Incentive Plan (Detail) (USD $)
 1 Months Ended 3 Months Ended
Feb. 28, 2015
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock outstanding, beginning balance, Shares   1,207,009us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Granted 25,567us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 25,567us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Vested   (175,122)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Forfeited/canceled   (8,924)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Stock outstanding, ending balance, Shares   1,048,530us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Unrecognized stock-based compensation expense as of March 31, 2015   $ 28,221,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Weighted average remaining vesting period (years) as of March 31, 2015   3 years 11 months 12 days
Nonvested weighted average grant date fair value per share, beginning balance   $ 18.23us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Weighted average grant date fair value per share, Granted $ 38.58us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 38.58us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Weighted average grant date fair value, Vested   $ 14.59us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
Weighted average grant date fair value, Transferred   $ 14.54mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredInPeriodWeightedAverageGrantDateFairValue
Weighted average grant date fair value, Forfeited/canceled   $ 20.71us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
Nonvested weighted average grant date fair value per share, ending balance   $ 19.32us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Restricted Stock [Member] | Non-employee directors [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock outstanding, beginning balance, Shares   42,882us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_NonEmployeeDirectorMember
Stock outstanding, ending balance, Shares   42,882us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_NonEmployeeDirectorMember
Unrecognized stock-based compensation expense as of March 31, 2015   444,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_NonEmployeeDirectorMember
Weighted average remaining vesting period (years) as of March 31, 2015   1 year 10 months 13 days
Restricted Stock Units (RSUs) [Member] | Employees [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock outstanding, beginning balance, Shares   516,437us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Granted 15,847us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember 		15,847us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Vested   (53,972)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Transferred   (6,877)mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Forfeited/canceled   (3,422)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Stock outstanding, ending balance, Shares   468,013us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Unrecognized stock-based compensation expense as of March 31, 2015   9,988,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_EmployeeStockMember
Weighted average remaining vesting period (years) as of March 31, 2015   4 years 3 months 15 days
Restricted Stock Units (RSUs) [Member] | Independent Contractors [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock outstanding, beginning balance, Shares   647,690us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Granted 9,720us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember 		9,720us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Vested   (121,150)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Transferred   6,877mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Forfeited/canceled   (5,502)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Stock outstanding, ending balance, Shares   537,635us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Unrecognized stock-based compensation expense as of March 31, 2015   $ 17,789,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= mmi_IndependentContractorsMember
Weighted average remaining vesting period (years) as of March 31, 2015   3 years 9 months 29 days