The amount of deposit held by the entity from Provincial Governments.

No definition available.

Name:	bma_DepositFromProvincialGovernments
Namespace Prefix:	bma_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Deposits liability related to court deposits.

+ References

No definition available.

+ Details

Name:	bma_DepositsLiabilityRelatedToCourtDeposits
Namespace Prefix:	bma_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discription of business and nature of operation [line items]

+ References

No definition available.

+ Details

Name:	bma_DiscriptionOfBusinessAndNatureOfOperationLineItems
Namespace Prefix:	bma_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of Shares Acquired to Common Shares and Votes

+ References

No definition available.

+ Details

Name:	bma_PercentageOfSharesAcquiredToCommonSharesAndVotes
Namespace Prefix:	bma_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Shares Acquired

+ References

No definition available.

+ Details

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Namespace Prefix:	bma_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock exchange rate.

+ References

No definition available.

+ Details

Name:	bma_StockExchangeRate
Namespace Prefix:	bma_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of loans to government made by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_LoansToGovernment
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of shares issued by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_NumberOfSharesIssued
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The nominal value per share.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 79
-Subparagraph a
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79_a_iii&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_ParValuePerShare
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ifrs-full_CounterpartiesAxis=bma_MisionesProvincialGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CounterpartiesAxis=bma_SaltaProvincialGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CounterpartiesAxis=bma_JujuyProvincialGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CounterpartiesAxis=bma_BancoDelTucumanSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=bma_ClassCommonRegisteredNonendorsableSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=ifrs-full_MajorBusinessCombinationMember
Namespace Prefix:
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Operations of the Bank - Additional Information (Detail) - ARS ($) $ / shares in Units, $ in Thousands	Aug. 10, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Discription Of Business And Nature Of Operation [line items]
Number of shares		639,413,408	639,413,408	669,663,021
Misiones Provincial Government [member]
Discription Of Business And Nature Of Operation [line items]
Deposits liability		$ 16,239,739	$ 9,305,984
Deposits liability related to court deposits		808,570	942,301
Salta Provincial Government [member]
Discription Of Business And Nature Of Operation [line items]
Deposits liability		3,777,068	5,933,781
Deposits liability related to court deposits		1,240,932	1,235,163
Jujuy Provincial Government [member]
Discription Of Business And Nature Of Operation [line items]
Deposits liability		10,910,810	1,607,209
Deposits liability related to court deposits		1,168,418	874,074
Banco del Tucuman SA [member]
Discription Of Business And Nature Of Operation [line items]
Deposits liability		14,274,476	4,902,149
Deposits liability related to court deposits		3,536,735	3,342,313
Bank granted loans to government		$ 2,860,617	$ 7,606,547
Banco del Tucuman SA [member] \| Class B common registered non-endorsable shares [member]
Discription Of Business And Nature Of Operation [line items]
Shares acquired	43,960
Face value per share	$ 100
Percentage of shares acquired to common shares and votes	10.00%
Banco del Tucuman SA [member] \| Major business combination [member]
Discription Of Business And Nature Of Operation [line items]
Face value per share	$ 1
Stock exchange rate	$ 0.65258
Number of shares	15,662