Annual report pursuant to Section 13 and 15(d)

Notes Payable to Former Stockholders - Additional Information (Detail)

v2.4.1.9
Notes Payable to Former Stockholders - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Notes Payable [Line Items]      
Accrued interest expense pertaining to Notes $ 396,000us-gaap_InterestPayableCurrent $ 425,000us-gaap_InterestPayableCurrent  
Interest expense 1,651,000us-gaap_InterestExpense 105,000us-gaap_InterestExpense 4,000us-gaap_InterestExpense
Accrued interest expense related to IPO   318,000mmi_InterestExpenseRelatedToNotesPayablePriorToIpo  
Payments of principal and interest amount 1,500,000us-gaap_DebtInstrumentPeriodicPayment    
Payments pertained to interest 618,000us-gaap_DebtInstrumentPeriodicPaymentInterest    
Payments pertained to principal 851,000us-gaap_RepaymentsOfNotesPayable    
Restricted Stock - Notes Payable [Member]      
Notes Payable [Line Items]      
Unsecured notes interest rate 5.00%us-gaap_LongTermDebtPercentageBearingFixedInterestRate
/ us-gaap_AwardTypeAxis
= mmi_RestrictedStockNotesPayableMember
   
Unsecured notes maturity date Apr. 14, 2020    
SARs - Notes Payable [Member]      
Notes Payable [Line Items]      
Unsecured notes interest rate 5.00%us-gaap_LongTermDebtPercentageBearingFixedInterestRate
/ us-gaap_AwardTypeAxis
= mmi_StockAppreciationRightsSarsNotesPayableMember
   
Unsecured notes maturity date Jun. 30, 2020    
Notes Payable to Former Stockholders [Member]      
Notes Payable [Line Items]      
Interest expense $ 591,000us-gaap_InterestExpense
/ us-gaap_ShortTermDebtTypeAxis
= mmi_NotesPayableToFormerStockholdersMember
$ 103,000us-gaap_InterestExpense
/ us-gaap_ShortTermDebtTypeAxis
= mmi_NotesPayableToFormerStockholdersMember