XML 113 R98.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Subsequent Event (Details) - 2 months ended Feb. 27, 2018 - Other disposals of assets [member] CAD / shares in Units, $ in Millions | CAD CAD / shares | USD ($)
--- | --- | ---
Corex Gold Corp [Member] |  |
Disclosure of non-adjusting events after reporting period [line items] |  |
Sale of stock (CAD per share) | CAD / shares | CAD 0.13 |
Proceeds from divestiture of businesses |  | $ 2.6
Gain on sale of business |  | 0.6
Weighted average share price | CAD | CAD 0.10 |
AuRico Metals [Member] |  |
Disclosure of non-adjusting events after reporting period [line items] |  |
Sale of stock (CAD per share) | CAD / shares | CAD 1.80 |
Proceeds from divestiture of businesses |  | 22.1
Gain on sale of business |  | $ 13.2
Weighted average share price | CAD | CAD 0.72 |

X
- Definition Sale of Stock, Price Per Share1 + References No definition available. + Details
Name: | agi_SaleofStockPricePerShare1
Namespace Prefix: | agi_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

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_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The gains (losses) on available-for-sale financial assets. [Refer: Financial assets available-for-sale] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 20 -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_20_a_ii&doctype=Standard&book=B -URIDate 2017-03-09 + Details
Name: | ifrs-full_GainsLossesOnAvailableforsaleFinancialAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow from the disposal or maturity of available-for-sale financial assets. [Refer: Financial assets available-for-sale] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_16&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ProceedsFromDisposalOrMaturityOfAvailableforsaleFinancialAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The weighted average share price. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_c&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_WeightedAverageSharePrice
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=ifrs-full_OtherDisposalsOfAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | agi_DisposalGroupName1Axis=agi_CorexGoldCorpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | agi_DisposalGroupName1Axis=agi_AuRicoMetalsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |