Financial instruments risk, Liquidity risk (Details) - MXN ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Liquidity risk [Abstract]
Trade payables	$ 437,005	$ 228,959
Accounts payable and accrued expenses	470,068	525,108
Related parties	144,966	1,458
Leasing liabilities	409,875	355,513
Financial debt	$ 122,707	$ 182,729
Liquidity Risk [Member]
Liquidity risk [Abstract]
Percentage of financial liabilities due in next 12 months	47.00%	35.00%
Liquidity Risk [Member] \| In 6 Months [Member]
Liquidity risk [Abstract]
Trade payables	$ 437,005	$ 228,959
Accounts payable and accrued expenses	0	0
Related parties	0
Leasing liabilities	86,597	29,465
Financial debt	19,041	52,125
Total financial liabilities	542,643	310,549
Liquidity Risk [Member] \| 6 to 12 Months [Member]
Liquidity risk [Abstract]
Trade payables	0	0
Accounts payable and accrued expenses	470,068	525,108
Related parties	144,966
Leasing liabilities	34,781	28,780
Financial debt	38,065	76,960
Total financial liabilities	687,880	630,848
Liquidity Risk [Member] \| 1 to 4 Years [Member]
Liquidity risk [Abstract]
Trade payables	0	0
Accounts payable and accrued expenses	0	23,521
Related parties	0
Leasing liabilities	238,404	193,811
Financial debt	54,283	48,227
Total financial liabilities	292,687	265,559
Liquidity Risk [Member] \| More than 4 Years [Member]
Liquidity risk [Abstract]
Trade payables	0	0
Accounts payable and accrued expenses	0	0
Related parties	0
Leasing liabilities	50,093	103,457
Financial debt	11,318	5,417
Total financial liabilities	$ 61,411	$ 108,874

No definition available.

Name:	gtmay_LiquidityRiskAbstract
Namespace Prefix:	gtmay_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Refers to the percentage of the entity's financial liabilities that are due in one year or less.

+ References

No definition available.

+ Details

Name:	gtmay_PercentageOfFinancialLiabilitiesClassifiedCurrent
Namespace Prefix:	gtmay_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of outstanding funds that the entity is obligated to repay.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_55&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_Borrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of current accrued expenses and other current liabilities. [Refer: Accruals; Other current liabilities]

+ References

+ Details

Name:	ifrs-full_CurrentAccruedExpensesAndOtherCurrentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 25
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2021-en-r&anchor=para_25&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_FinancialLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2021-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2021-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_LeaseLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of current payables due to related parties. [Refer: Related parties [member]; Payables to related parties]

+ References

+ Details

Name:	ifrs-full_TradeAndOtherCurrentPayablesToRelatedParties
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current amount of payment due to suppliers for goods and services used in entity's business. [Refer: Current liabilities; Trade payables]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 78
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_78&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 70
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_70&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_TradeAndOtherCurrentPayablesToTradeSuppliers
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ifrs-full_TypesOfRisksAxis=ifrs-full_LiquidityRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanThreeMonthsAndNotLaterThanSixMonthsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanSixMonthsAndNotLaterThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=gtmay_LaterThanOneYearAndNotLaterThanFourYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=gtmay_LaterThanFourYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: