Finance costs (Details Textuals) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Minera Yanacocha SRL and subsidiary [Member]
Expense due to unwinding of discount on provisions	$ 21,769,000	$ 14,104,000	$ 22,075,000

The amount of expense recognised due to the unwinding of the discount on provisions, resulting from the effect of the passage of time. [Refer: Other provisions]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2017-03-09

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