Name:	mmab_DiscontinuedOperationBondsGainsLosses
Namespace Prefix:	mmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of interest income attributable to the disposal group, including a component of the entity (discontinued operation).

No definition available.

Name:	mmab_DiscontinuedOperationInterestIncome
Namespace Prefix:	mmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of other expenses attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

No definition available.

Name:	mmab_OtherDiscontinuedExpenses
Namespace Prefix:	mmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Other income (loss) amounts, net of tax expense or benefit, relating to a disposal group that is classified as a component of the entity, exclusive of the following elsewhere enumerated categories: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Name:	us-gaap_DiscontinuedOperationAmountOfOtherIncomeLossFromDispositionOfDiscontinuedOperationNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of difference between the carrying amount and the sales price of real estate properties sold as part of discontinued operations.

No definition available.

Name:	us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 19

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683