Inventories - Additional information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Inventory [Line Items]
Cost of inventories recognised as expense during period	$ 367,310	$ 296,218
Production costs	445,183	334,839
Gold, Lead, and Zinc Concentrate
Inventory [Line Items]
Production costs	2,122	632
Depreciation charges	$ 206	$ 1,894

The amount of depreciation expense. Depreciation is the systematic allocation of depreciable amounts of tangible assets over their useful lives.

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

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration