XML 96 R62.htm IDEA: XBRL DOCUMENT
v3.22.1

Share Capital (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Equity Financing [Line Items] |  |
Stock Repurchased Authorization | 29,994,398 |
Repurchased Shares Price Per Share | $ 7.39 | $ 4.89
Other loss (note 14) | $ (7.2) | $ (3.7)
Dividends recognised as distributions to owners |  | $ 23.9
Share capital [Member] |  |
Equity Financing [Line Items] |  |
Shares repurchased and cancelled (in shares) | 1,583,562 | 1,133,561
Expected cash outflow on redemption or repurchase of puttable financial instruments | $ 11.7 |
Dividend reinvestment plan and share purchase plan (in shares) | 656,473 | 1,186,205
Dividend reinvestment plan (ii) | $ 4.6 | $ 10.0
Shares Repurchased |  | 5.5
Dividends recognised as distributions to owners |  | $ 1.7

X
- Definition [Line Items] for Equity Financing [Table] + References No definition available. + Details
Name: | agi_EquityFinancingLineItems
Namespace Prefix: | agi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Shares Issued Through DRIP + References No definition available. + Details
Name: | agi_NumberOfSharesIssuedThroughDRIP
Namespace Prefix: | agi_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition other nonoperating income (expense) + References No definition available. + Details
Name: | agi_OtherNonoperatingIncomeExpense1
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Repurchased Shares Price Per Share + References No definition available. + Details
Name: | agi_RepurchasedSharesPricePerShare
Namespace Prefix: | agi_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Shares Repurchased + References No definition available. + Details
Name: | agi_SharesRepurchased
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Stock Issued During Period, Value, DRIP + References No definition available. + Details
Name: | agi_StockIssuedDuringPeriodValueDRIP
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Stock Repurchased Authorization + References No definition available. + Details
Name: | agi_StockRepurchasedAuthorization
Namespace Prefix: | agi_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of dividends recognised as distributions to owners. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 107 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_107&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_DividendsPaid
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The expected cash outflow on the redemption or repurchase of puttable financial instruments classified as equity. [Refer: Liquidity risk [member]; Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 136A -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_136A_c&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_ExpectedCashOutflowOnRedemptionOrRepurchaseOfPuttableFinancialInstruments
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in the number of ordinary shares issued. [Refer: Ordinary shares [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_112_c&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_IncreaseDecreaseInNumberOfOrdinarySharesIssued
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ComponentsOfEquityAxis=ifrs-full_IssuedCapitalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |