Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v2.4.1.9
Income Taxes - Additional Information (Detail)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Income Taxes [Line Items]    
Effective income tax rate 41.40%us-gaap_EffectiveIncomeTaxRateContinuingOperations 41.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations
Estimated 2015 annual effective tax rate [Member]    
Income Taxes [Line Items]    
Effective income tax rate 40.70%us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_TypeOfArrangementAxis
= mmi_ForecastedTwoThousandAndFifteenTaxRateMember