Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions - Additional Information (Detail)

v2.4.1.9
Related-Party Transactions - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Related Party Transaction [Line Items]      
Accounts payable and other accrued expenses - related party $ 97,000us-gaap_DueToRelatedPartiesCurrent $ 506,000us-gaap_DueToRelatedPartiesCurrent  
Transition services agreement date Oct. 01, 2013    
Real estate brokerage commissions and financing fees from transactions with former parent, Marcus & Millichap Company 1,300,000us-gaap_RevenueFromRelatedParties 735,000us-gaap_RevenueFromRelatedParties 1,100,000us-gaap_RevenueFromRelatedParties
Commission expenses for transactions with former parent, Marcus & Millichap Company 816,000us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty 441,000us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty 711,000us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Rent expense for lease 16,700,000us-gaap_OperatingLeasesRentExpenseNet 15,700,000us-gaap_OperatingLeasesRentExpenseNet 14,500,000us-gaap_OperatingLeasesRentExpenseNet
Aggregate principal amount outstanding for employee notes receivable 378,000us-gaap_DueFromEmployees 418,000us-gaap_DueFromEmployees  
Sweep arrangement termination date Jun. 30, 2013    
MMC [Member]      
Related Party Transaction [Line Items]      
Rent expense for lease 438,000us-gaap_OperatingLeasesRentExpenseNet
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		398,000us-gaap_OperatingLeasesRentExpenseNet
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		278,000us-gaap_OperatingLeasesRentExpenseNet
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
Lease expiration date May 31, 2022    
Interest income earned from MMC 0us-gaap_InterestIncomeRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		74,000us-gaap_InterestIncomeRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		147,000us-gaap_InterestIncomeRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
MMC [Member] | Shared Services [Member]      
Related Party Transaction [Line Items]      
General and administrative expense 4,300,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_SharedServicesMember 		4,800,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_SharedServicesMember 		 
MMC [Member] | Shared Services [Member] | Health Insurance Premium [Member]      
Related Party Transaction [Line Items]      
General and administrative expense 3,200,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis
= mmi_HealthInsurancePremiumMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_SharedServicesMember 		3,500,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis
= mmi_HealthInsurancePremiumMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_SharedServicesMember 		 
MMC [Member] | Transition Services Agreement [Member]      
Related Party Transaction [Line Items]      
General and administrative expense 1,300,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		824,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		 
Accounts payable and other accrued expenses - related party 97,000us-gaap_DueToRelatedPartiesCurrent
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		506,000us-gaap_DueToRelatedPartiesCurrent
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		 
MMC [Member] | Transition Services Agreement [Member] | Health Insurance Premium [Member]      
Related Party Transaction [Line Items]      
General and administrative expense $ 1,000,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis
= mmi_HealthInsurancePremiumMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		$ 687,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis
= mmi_HealthInsurancePremiumMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		 
Mr. Marcus [Member]      
Related Party Transaction [Line Items]      
Percentage of ownership in diluted shares 65.00%mmi_PercentageOfIndirectOwnershipInterest
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		   
Shares for future sale 4,600,000mmi_CommonStockRegisteredForFutureSale
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		   
Registration Statement date Feb. 06, 2015