Annual report pursuant to Section 13 and 15(d)

Income Taxes - Components of Provision for Income Taxes and Income before Provision for Income Taxes (Detail)

v2.4.1.9
Income Taxes - Components of Provision for Income Taxes and Income before Provision for Income Taxes (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Provision Benefit For Income Taxes [Line Items]      
Income tax expense at the federal statutory rate of 35% $ 29,044us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ 7,679us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ 17,305us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
State income tax expenses, net of federal benefit 3,622us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 985us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 2,423us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
Permanent difference related to compensation charges 163mmi_IncomeTaxReconciliationPermanentDifferences 3,445mmi_IncomeTaxReconciliationPermanentDifferences  
Other 181us-gaap_IncomeTaxReconciliationOtherReconcilingItems 361us-gaap_IncomeTaxReconciliationOtherReconcilingItems 8us-gaap_IncomeTaxReconciliationOtherReconcilingItems
Change in valuation allowance 442us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount    
Provision for income taxes 33,452us-gaap_IncomeTaxExpenseBenefit 13,735us-gaap_IncomeTaxExpenseBenefit 21,507us-gaap_IncomeTaxExpenseBenefit
Tax-sharing agreement [Member]      
Provision Benefit For Income Taxes [Line Items]      
Differences due to tax-sharing agreement   $ 1,265us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate
/ us-gaap_TypeOfArrangementAxis
= mmi_TaxSharingAgreementMember
$ 1,771us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate
/ us-gaap_TypeOfArrangementAxis
= mmi_TaxSharingAgreementMember