Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans - Summary of Restricted Common Stock Activity - Pre-IPO (Detail)

v2.4.1.9
Stock-Based Compensation Plans - Summary of Restricted Common Stock Activity - Pre-IPO (Detail) (USD $)
 1 Months Ended 12 Months Ended 10 Months Ended 12 Months Ended
Dec. 31, 2014
Nov. 30, 2014
Aug. 31, 2014
May 31, 2014
Feb. 28, 2014
Dec. 31, 2014
Oct. 31, 2013
Dec. 31, 2012
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Outstanding, beginning balance, Shares           913,915us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber      
Issued upon exercise of stock options 216,411us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 14,222us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 18,820us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 61,655us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 38,088us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 349,196us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod      
Outstanding, ending balance, Shares 1,207,009us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber         1,207,009us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber      
Nonvested weighted average grant date fair value per share, beginning balance           $ 14.46us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue      
Nonvested weighted average grant date fair value per share, ending balance $ 18.23us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue         $ 18.23us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue      
MMREIS Common Stock [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Exchange of common stock             234,489us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_StatementClassOfStockAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesCommonStockMember 		234,489us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_StatementClassOfStockAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesCommonStockMember 		 
MMREIS Common Stock [Member] | MMREIS Managing Directors [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Exchange of common stock             28,749us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_StatementClassOfStockAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesCommonStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesManagingDirectorsMember 		   
Restricted Common Stock [Member] | Pre-IPO [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Outstanding, beginning balance, Shares             27,999us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		24,499us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		27,999us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
Issued upon exercise of stock options               3,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		750us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
Outstanding, ending balance, Shares               27,999us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		 
Restricted common stock vested ending balance, Shares               22,682mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVested
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		 
Restricted common stock unvested ending balance, Shares               5,317mmi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedOutstanding
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		 
Nonvested weighted average grant date fair value per share, beginning balance             23.67us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		23.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		$ 23.67us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
Issued/Granted, Weighted-Average Grant Date Fair Value               25.87us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		$ 28.86us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
Exchange of common stock, Weighted-Average Grant Date Fair Value               0mmi_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsExchangedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		$ 0mmi_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsExchangedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
Nonvested weighted average grant date fair value per share, ending balance               23.67us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember 		 
Restricted Common Stock [Member] | Pre-IPO [Member] | MMREIS Common Stock [Member] | MMREIS Managing Directors [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Exchange of common stock                 (28,749)us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_AwardTypeAxis
= mmi_RestrictedCommonStockMember
/ us-gaap_StatementClassOfStockAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesCommonStockMember
/ us-gaap_StatementScenarioAxis
= mmi_PreIpoMember
/ us-gaap_TitleOfIndividualAxis
= mmi_MarcusAndMillichapRealEstateInvestmentServicesManagingDirectorsMember