XML 86 R58.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Selected Balance Sheet Data - Additional Information (Detail) |  |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jan. 01, 2019 | Jan. 01, 2018 | Jan. 01, 2017 | Jan. 01, 2014 | Dec. 31, 2019 USD ($) Installments | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Mar. 31, 2013 USD ($)
Schedule Of Accrued Expenses [Line Items] |  |  |  |  |  |  |  |
SARs frozen liability amount |  |  |  |  | $ 18,122,000 | $ 19,299,000 |  |
Interest expense |  |  |  |  | $ 1,388,000 | 1,400,000 | $ 1,496,000 |
Maximum payment deferral period for certain commissions payable |  |  |  |  | 3 years |  |  |
Mortgage servicing rights [Member] |  |  |  |  |  |  |  |
Schedule Of Accrued Expenses [Line Items] |  |  |  |  |  |  |  |
Servicing portfolio of commercial real estate loans, unpaid principal balance |  |  |  |  | $ 1,600,000,000 | 1,600,000,000 |  |
Escrow Funds |  |  |  |  | $ 2,600,000 | 2,100,000 |  |
SARs [Member] |  |  |  |  |  |  |  |
Schedule Of Accrued Expenses [Line Items] |  |  |  |  |  |  |  |
SARs frozen liability amount |  |  |  |  |  |  |  | $ 20,000,000.0
SARs liability frozen value date |  |  |  |  | Mar. 31, 2013 |  |  |
SARs liability number of annual installments | Installments |  |  |  |  | 10 |  |  |
SARs liability interest accrual commencement date |  |  |  |  | Jan. 01, 2014 |  |  |
SARs liability interest accrual rates | 4.684% | 4.409% | 4.446% |  |  |  |  |
Interest expense |  |  |  |  | $ 904,000 | 891,000 | $ 931,000 |
Treasury note term |  |  |  | 10 years |  |  |  |
Base spread on SARs liability variable rate |  |  |  | 2.00% |  |  |  |
Estimated payouts description |  |  |  |  | Estimated payouts within the next twelve months for participants that have separated from service have been classified as current. |  |  |
Payments made during the period |  |  |  |  | $ 1,800,000 | 1,700,000 |  |
Sars liability principal paid |  |  |  |  | 185,000 |  |  |
Sars liability interest paid |  |  |  |  | $ 1,600,000 |  |  |
Deferred Compensation Liability [Member] |  |  |  |  |  |  |  |
Schedule Of Accrued Expenses [Line Items] |  |  |  |  |  |  |  |
Estimated payouts description |  |  |  |  | Estimated payouts within the next twelve months for participants that have separated from service or elected in service payout have been classified as current. |  |  |
Deferred Compensation Liability, Minimum Payout Period |  |  |  |  | 2 years |  |  |
Deferred Compensation Liability, Maximum Payout Period |  |  |  |  | 15 years |  |  |
Fair value of deferred compensation plan assets |  |  |  |  | 110.00% |  |  |
Payments made during the period |  |  |  |  | $ 1,600,000 | $ 1,300,000 |  |

X
- Definition Maximum payment deferral period for certain commissions payable. + References No definition available. + Details
Name: | mmi_CommissionPayablePaymentDeferralPeriod
Namespace Prefix: | mmi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period participants can elect to receive payouts under the Deferred Compensation Plan. + References No definition available. + Details
Name: | mmi_DeferredCompensationLiabilityMaximumPayoutPeriod
Namespace Prefix: | mmi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period participants can elect to receive payouts under the Deferred Compensation Plan. + References No definition available. + Details
Name: | mmi_DeferredCompensationLiabilityMinimumPayoutPeriod
Namespace Prefix: | mmi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount the Company may, in its sole and absolute discretion, elect to withdraw at any time all or a portion of the amount by which the fair market value of the Deferred Compensation Plan's assets exceeds the stated percentage of the aggregate amount credited to the Deferred Compensation Plan's participants' accounts. + References No definition available. + Details
Name: | mmi_DeferredCompensationPlanPercentage
Namespace Prefix: | mmi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated payouts description. + References No definition available. + Details
Name: | mmi_EstimatedPayoutsDescription
Namespace Prefix: | mmi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition SARs liability number of annual installments settlement period. + References No definition available. + Details
Name: | mmi_NumberOfAnnualInstallments
Namespace Prefix: | mmi_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Payments for deferred compensation and commissions. + References No definition available. + Details
Name: | mmi_PaymentsForDeferredCompensationAndCommissions
Namespace Prefix: | mmi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Payments (consisting of principal or interest or principal and interest) for stock appreciation rights liability. + References No definition available. + Details
Name: | mmi_PaymentsForSarsLiability
Namespace Prefix: | mmi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sars liability, Periodic Payment, Interest. + References No definition available. + Details
Name: | mmi_SarsLiabilityPeriodicPaymentInterest
Namespace Prefix: | mmi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sars liability, Periodic Payment, principal. + References No definition available. + Details
Name: | mmi_SarsLiabilityPeriodicPaymentPrincipal
Namespace Prefix: | mmi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Schedule Of Accrued Expenses [Line Items] + References No definition available. + Details
Name: | mmi_ScheduleOfAccruedExpensesLineItems
Namespace Prefix: | mmi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition SARS liability frozen value date. + References No definition available. + Details
Name: | mmi_StockAppreciationRightsLiabilityFrozenValueDate
Namespace Prefix: | mmi_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition SARS liability interest accrual commencement date + References No definition available. + Details
Name: | mmi_StockAppreciationRightsLiabilityInterestAccrualCommencementDate
Namespace Prefix: | mmi_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Interest accrual rate for the outstanding balance on the SARs liability. + References No definition available. + Details
Name: | mmi_StockAppreciationRightsLiabilityInterestAccrualRate
Namespace Prefix: | mmi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate carrying value (includes principal and accrued interest) as of the balance sheet date of non-current deferred compensation associated with Stock Appreciation Rights payable to each participant in installments upon retirement or departure under terms of the agreement. + References No definition available. + Details
Name: | mmi_StockAppreciationRightsLiabilityNoncurrent
Namespace Prefix: | mmi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Treasury note term rate used to determine SARs liability interest accrual rate. + References No definition available. + Details
Name: | mmi_TreasuryNoteRateTerm
Namespace Prefix: | mmi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_EscrowDeposit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (210.5-03(11)) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260 + Details
Name: | us-gaap_InterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118948506&loc=d3e107314-111719 + Details
Name: | us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mmi_MortgageServicingRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_StockAppreciationRightsSARSMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=mmi_DeferredCompensationLiabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |