Number of Variable Interest Entities

No definition available.

Name:	mmac_NumberOfVariableInterestEntities
Namespace Prefix:	mmac_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Variable Interest Entity, Maximum Committed Financial or Other Support

+ References

No definition available.

+ Details

Name:	mmac_VariableInterestEntityMaximumCommittedFinancialOrOtherSupport
Namespace Prefix:	mmac_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetReportedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=52262685&loc=d3e5728-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=52262685&loc=d3e5747-111685

+ Details

Name:	us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

+ Details

Name:	us-gaap_VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_UsRealEstatePartnershipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_U.s.RealEstatePartnershipsFormedInQ42014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_U.s.RealEstatePartnershipsOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_MunimaeTeiHoldingsLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_IhsManagedFundsAndVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_EquityInIncomeFromSawhfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_IhsResidentialPartnersOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_IhsFundTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mmac_SolarFacilitiesInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

INVESTMENTS IN PARTNERSHIPS (Narrative) (Details) $ in Thousands, ZAR in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Jul. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2016 USD ($) entity	Jun. 30, 2016 ZAR	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					$ 237,474	$ 260,441
Loans and Leases Receivable, Net Amount, Total					24,754	7,928
U.S. Real Estate Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					$ 27,974	29,633
Payments to acquire equity method investments		$ 8,800
Equity method investment, ownership percentage		80.00%		33.00%	33.00%
Number of Variable Interest Entities \| entity			5
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net					$ 11,500	13,400
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount					11,500	20,300
U.S. Real Estate Partnerships formed in Q4 2014[Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					16,400
U.S. Real Estate Partnerships, Other [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					6,200
MuniMae TEI Holdings, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					5,300
IHS Managed Funds and Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					2,734	2,501
Equity In Income From SAWHF [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					1,100
IHS Residential Partners One [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					1,600
Variable Interest Entity, Maximum Committed Financial or Other Support \| ZAR				ZAR 180
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount					12,000	11,700
IHS Fund Two [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					100
Solar Facilities Investment [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments					$ 51,248	$ 50,521
Payments to acquire equity method investments	$ 25,000		$ 50,000
Equity method investment, ownership percentage				50.00%	50.00%
Minimum [Member] \| IHS Managed Funds and Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage				1.80%	1.80%
Maximum [Member] \| IHS Managed Funds and Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage				4.25%	4.25%