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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_55&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The adjustment to the basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2024-01-01
-Paragraph 7
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_7&doctype=Standard
-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	dtr-2022:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of undrawn borrowing facilities that may be available for future operating activities and to settle capital commitments. [Refer: Capital commitments]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 50
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_50_a&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The maturity of borrowings.

+ References

No definition available.

+ Details

Name:	mag_BorrowingsMaturityTerm
Namespace Prefix:	mag_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of commitment fees recognised as expense.

+ References

No definition available.

+ Details

Name:	mag_CommitmentFeesRecognisedAsExpense
Namespace Prefix:	mag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	mag_Statement1LineItems
Namespace Prefix:	mag_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfInterestRatesAxis=mag_SecuredOvernightFinancingRateSOFRMember
Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Note 12 - Debt Facility (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Oct. 04, 2023	Dec. 31, 2024
Secured overnight financing rate (SOFR) [member] \| Bottom of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis		2.00%
Secured overnight financing rate (SOFR) [member] \| Top of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis		4.00%
Senior secured revolving credit facility [member]
Statement Line Items [Line Items]
Undrawn borrowing facilities	$ 40,000
Borrowings, maturity term (Month)	34 months
Total borrowings		$ 0
Commitment fees recognised as expense		$ 200
Senior secured revolving credit facility [member] \| Secured overnight financing rate (SOFR) [member] \| Bottom of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis	2.00%
Senior secured revolving credit facility [member] \| Secured overnight financing rate (SOFR) [member] \| Top of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis	4.00%
Senior secured revolving credit facility [member] \| Commitment fee as a percentage of undisbursed loan amount [member] \| Bottom of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis	0.50%
Senior secured revolving credit facility [member] \| Commitment fee as a percentage of undisbursed loan amount [member] \| Top of range [member]
Statement Line Items [Line Items]
Borrowings, adjustment to interest rate basis	0.75%