XML 76 R53.htm IDEA: XBRL DOCUMENT
v3.19.1

Significant accounting policies - Share-based compensation (Details) - Performance shares | 12 Months Ended
--- | ---
Dec. 31, 2018
Grants prior to 2015 | Bottom of range |
Disclosure of terms and conditions of share-based payment arrangement [line items] |
Share-based compensation arrangement vesting rights, percentage | 50.00%
Grants prior to 2015 | Top of range |
Disclosure of terms and conditions of share-based payment arrangement [line items] |
Share-based compensation arrangement vesting rights, percentage | 120.00%
Grants subsequent to 2015 | Bottom of range |
Disclosure of terms and conditions of share-based payment arrangement [line items] |
Share-based compensation arrangement vesting rights, percentage | 25.00%
Grants subsequent to 2015 | Top of range |
Disclosure of terms and conditions of share-based payment arrangement [line items] |
Share-based compensation arrangement vesting rights, percentage | 150.00%

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage1 + References No definition available. + Details
Name: | mx_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardVestingRightsPercentage1
Namespace Prefix: | mx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=mx_PerformanceShares1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mx_Vesting1Axis=mx_SharebasedCompensationAwardTrancheOne1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mx_Vesting1Axis=mx_SharebasedCompensationAwardTrancheTwo1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |