XML 86 R70.htm IDEA: XBRL DOCUMENT
v3.20.4

Supplemental Cash Flow Information (Other Non-cash Items) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Disclosure of Cash Flow Statement [Abstract] |  |
Unrealized (gain) loss on non-hedging derivatives | $ (0.7) | $ 0.6
Payment for reclamation activities | (3.5) | (2.0)
Adjustments for interest income | (1.5) | (3.4)
Adjustments for increase (decrease) in insurance, reinsurance and investment contract liabilities | (1.7) | (1.8)
Distribution of Share Based Compensation | (3.5) | (3.8)
Reduction of obligation to renounce flow-through exploration expenditures | (1.0) | (0.6)
Loss on disposal of assets | 1.0 | 0.7
Non-cash proceeds on sale of non-core royalties | 0.0 | (8.0)
Other | 2.8 | (0.7)
Other adjustments for non-cash items | $ (5.1) | $ (12.2)

X
- Definition Disclosure of Cash Flow Statement [Abstract] + References No definition available. + Details
Name: | agi_DisclosureofCashFlowStatementAbstract
Namespace Prefix: | agi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Distribution of Share Based Compensation + References No definition available. + Details
Name: | agi_DistributionOfShareBasedCompensation
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Noncash Net Realizable Value Adjustments + References No definition available. + Details
Name: | agi_NoncashNetRealizableValueAdjustments
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reduction of Obligation to Renounce Flow Through Exploration Costs + References No definition available. + Details
Name: | agi_ReductionofObligationtoRenounceFlowThroughExplorationCosts
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Unrealized Gain (Loss) on Derivatives1 + References No definition available. + Details
Name: | agi_UnrealizedGainLossonDerivatives1
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for gains (losses) on changes in the fair value of derivatives to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: At fair value [member]; Derivatives [member]; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForGainsLossesOnChangeInFairValueOfDerivatives
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for increase (decrease) in insurance, reinsurance and investment contract liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Investment contracts liabilities; Liabilities under insurance contracts and reinsurance contracts issued; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForIncreaseDecreaseInInsuranceReinsuranceAndInvestmentContractLiabilities
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for interest income expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Interest income; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForInterestIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The losses on disposals of non-current assets. [Refer: Non-current assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_LossesOnDisposalsOfNoncurrentAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for non-cash items to reconcile profit (loss) to net cash flow from (used in) operating activities that the entity does not separately disclose in the same statement or note. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_b&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_OtherAdjustmentsForNoncashItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of material non-cash items other than depreciation and amortisation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -Subparagraph i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_i&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_e&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_OtherMaterialNoncashItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration