XML 27 R12.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Inventory | 12 Months Ended
--- | ---
Dec. 31, 2017
Disclosure of inventories [Abstract] |
Inventory |
7. | INVENTORY
| December 31, 2017 | December 31, 2016
In-process precious metals | $131.6 |  | $120.7 |
Ore in stockpiles | 44.1 |  | 37.6 |
Parts and supplies | 41.5 |  | 35.7 |
Dore, refined precious metals and gold in concentrate | 12.7 |  | 13.5 |
| 229.9 |  | 207.5 |
Less: Long-term inventory | (68.7 | ) | (75.8 | )
| $161.2 |  | $131.7 |
Long term inventory consists of heap leach and long-term stockpiles of $68.7 million at December 31, 2017 (December 31, 2016 - $75.8 million) and are expected to be recovered after one year. The amount of inventories recognized in mining and processing costs for the year ended December 31, 2017 was $323.3 million (December 31, 2016 - $304.1 million). The amount of inventories recognized in amortization costs for the year ended December 31, 2017 was $125.6 million (December 31, 2016 - $119.0 million).

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

X
- Definition The entire disclosure for inventories. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 2 -IssueDate 2017-01-01 -Section Disclosure -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2017-03-01&anchor=sect_Disclosure&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_DisclosureOfInventoriesExplanatory
Namespace Prefix: | ifrs-full_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration