Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Detail)

v2.4.1.9
Related-Party Transactions - Additional Information (Detail) (USD $)
 3 Months Ended 0 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 18, 2015
Mar. 13, 2015
Dec. 31, 2014
Related Party Transaction [Line Items]          
Accounts payable and other accrued expenses - related party $ 273,000us-gaap_DueToRelatedPartiesCurrent       $ 97,000us-gaap_DueToRelatedPartiesCurrent
Transition services agreement date Oct. 01, 2013        
Real estate brokerage commissions and financing fees from transactions with former parent, Marcus & Millichap Company 1,000,000us-gaap_RevenueFromRelatedParties 60,000us-gaap_RevenueFromRelatedParties      
Commission expenses for transactions with former parent, Marcus & Millichap Company 627,000us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty 36,000us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty      
Aggregate principal amount outstanding for employee notes receivable 218,000us-gaap_DueFromEmployees       378,000us-gaap_DueFromEmployees
MMC [Member]          
Related Party Transaction [Line Items]          
Rent expense for lease 109,500us-gaap_OperatingLeasesRentExpenseNet
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		109,500us-gaap_OperatingLeasesRentExpenseNet
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember 		     
Lease expiration date May 31, 2022        
MMC [Member] | Transition Services Agreement [Member]          
Related Party Transaction [Line Items]          
General and administrative expense 50,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		1,100,000us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		     
Accounts payable and other accrued expenses - related party 273,000us-gaap_DueToRelatedPartiesCurrent
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		      97,000us-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 0us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= mmi_MarcusAndMillichapCompanyMember
/ us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis
= mmi_HealthInsurancePremiumMember
/ us-gaap_RelatedPartyTransactionAxis
= mmi_TransitionServicesAgreementMember 		1,000,000us-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 53.30%mmi_PercentageOfIndirectOwnershipInterest
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		       
Shares registered for future sale 4,600,000mmi_CommonStockRegisteredForFutureSale
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		       
Registration Statement date Feb. 06, 2015        
Proceeds from issuance of common stock 0us-gaap_ProceedsFromIssuanceOfCommonStock
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		       
New shares offered 0us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		       
Costs incurred in connection with registration statement to be reimbursed by Phoenix Investment Holdings, LLC. $ 113,000us-gaap_DueFromRelatedPartiesCurrent
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		       
Sale date of shares filed under registration statement Mar. 18, 2015        
Prospectus Supplement filing date Mar. 13, 2015        
Mr. Marcus [Member] | Underwriters [Member]          
Related Party Transaction [Line Items]          
Common stock sold by certain selling stockholders     600,000mmi_CommonStockSoldByCertainSellingStockholders
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_OverAllotmentOptionMember
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		   
Common stock selling price     $ 31.9925us-gaap_SharePrice
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_OverAllotmentOptionMember
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		   
Mr. Marcus [Member] | Selling Stockholders [Member]          
Related Party Transaction [Line Items]          
Common stock sold by certain selling stockholders     4,000,000mmi_CommonStockSoldByCertainSellingStockholders
/ us-gaap_SubsidiarySaleOfStockAxis
= mmi_SellingStockholdersMember
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		4,000,000mmi_CommonStockSoldByCertainSellingStockholders
/ us-gaap_SubsidiarySaleOfStockAxis
= mmi_SellingStockholdersMember
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember 		 
Common stock selling price     $ 31.9925us-gaap_SharePrice
/ us-gaap_SubsidiarySaleOfStockAxis
= mmi_SellingStockholdersMember
/ us-gaap_TitleOfIndividualAxis
= mmi_ChairmanAndFounderMember