DEBT (Subordinate Debt) (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Net premium and debt issue costs	$ 7,426
Carrying Value	151,340	$ 149,187
Subordinated Loan [Member] \| MMA Financial Holdings Inc. Debt [Member]
Debt Instrument [Line Items]
Principal amount of debt	88,488
Net premium and debt issue costs	7,557
Carrying Value	96,045
Subordinated Loan [Member] \| MFH Issue 1 [Member]
Debt Instrument [Line Items]
Principal amount of debt	26,130
Net premium and debt issue costs	2,299
Carrying Value	$ 28,429
Maturity Date	March 30, 2035
Coupon Interest Rate	3-month LIBOR plus 2.0%
Subordinated Loan [Member] \| MFH Issue 2 [Member]
Debt Instrument [Line Items]
Principal amount of debt	$ 23,760
Net premium and debt issue costs	2,102
Carrying Value	$ 25,862
Maturity Date	April 30, 2035
Coupon Interest Rate	3-month LIBOR plus 2.0%
Subordinated Loan [Member] \| MFH Issue 3 [Member]
Debt Instrument [Line Items]
Principal amount of debt	$ 13,696
Net premium and debt issue costs	1,120
Carrying Value	$ 14,816
Maturity Date	July 30, 2035
Coupon Interest Rate	3-month LIBOR plus 2.0%
Subordinated Loan [Member] \| MFH Issue 4 [Member]
Debt Instrument [Line Items]
Principal amount of debt	$ 24,902
Net premium and debt issue costs	2,036
Carrying Value	$ 26,938
Maturity Date	July 30, 2035
Coupon Interest Rate	3-month LIBOR plus 2.0%

Debt Instrument, Principal Amount

No definition available.

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

- Definition

The amount of debt discount (net of debt premium) and debt issuance cost that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

No definition available.

+ Details

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

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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

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

- Definition

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: 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(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=mmac_MmaFinancialHoldingsInc.DebtMember
Namespace Prefix:
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Balance Type:
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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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