XML 87 R69.htm IDEA: XBRL DOCUMENT v3.22.4

Share Capital (Schedule of Stock Options Range for Outstanding and Exercisable Shares) (Details)	12 Months Ended
	Dec. 31, 2022 shares $ / shares	Dec. 31, 2021 shares $ / shares	Dec. 31, 2020 shares $ / shares
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number of options outstanding (in shares) | shares	3,924,851	4,601,726	3,476,579
Outstanding weighted average exercise price (CAD per share) | $ / shares	$ 8.32	$ 7.47	$ 6.80
Weighted average remaining contractual life of options outstanding (years)	4 years 1 month 2 days
Number of options exercisable (in shares) | shares	2,237,735
Exercisable weighted average exercise price (CAD per share)) | $ / shares	$ 6.67
$6.01 - $7.00
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number of options outstanding (in shares) | shares	1,092,977
Outstanding weighted average exercise price (CAD per share) | $ / shares	$ 6.57
Weighted average remaining contractual life of options outstanding (years)	2 years 9 months 25 days
Number of options exercisable (in shares) | shares	1,092,977
Exercisable weighted average exercise price (CAD per share)) | $ / shares	$ 6.57
$7.01 - $8.00
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number of options outstanding (in shares) | shares	743,126
Outstanding weighted average exercise price (CAD per share) | $ / shares	$ 7.62
Weighted average remaining contractual life of options outstanding (years)	4 years 7 days
Number of options exercisable (in shares) | shares	477,026
Exercisable weighted average exercise price (CAD per share)) | $ / shares	$ 7.62
$8.01 - $9.00
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number of options outstanding (in shares) | shares	15,571
Outstanding weighted average exercise price (CAD per share) | $ / shares	$ 8.63
Weighted average remaining contractual life of options outstanding (years)	4 years 1 month 28 days
Number of options exercisable (in shares) | shares	6,048
Exercisable weighted average exercise price (CAD per share)) | $ / shares	$ 8.63
$9.01 - $11.00
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number of options outstanding (in shares) | shares	2,073,177
Outstanding weighted average exercise price (CAD per share) | $ / shares	$ 9.50
Weighted average remaining contractual life of options outstanding (years)	4 years 9 months 14 days
Number of options exercisable (in shares) | shares	661,684
Exercisable weighted average exercise price (CAD per share)) | $ / shares	$ 9.50

X

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfNumberAndWeightedAverageRemainingContractualLifeOfOutstandingShareOptionsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of share options outstanding in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_d&doctype=Standard
-URIDate 2022-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_i&doctype=Standard
-URIDate 2022-03-24

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause vi
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_vi&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_NumberOfOutstandingShareOptions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of share options exercisable in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause vii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_vii&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_NumberOfShareOptionsExercisableInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average exercise price of share options exercisable in a share-based payment arrangement. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause vii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_vii&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisableInSharebasedPaymentArrangement2019
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average exercise price of share options outstanding in a share-based payment arrangement. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_i&doctype=Standard
-URIDate 2022-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph b
-Clause vi
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_b_vi&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average remaining contractual life of outstanding share options. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45_d&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_WeightedAverageRemainingContractualLifeOfOutstandingShareOptions2019
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=agi_ExercisePriceRangeTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=agi_ExercisePriceRangeThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=agi_ExercisePriceRangeFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=agi_ExercisePriceRangeFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: