The percentage of the entity's revenue. [Refer: Revenue]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 8
-IssueDate 2017-01-01
-Paragraph 34
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_34&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_PercentageOfEntitysRevenue
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Financial risk factors - Credit risk (Details) - Credit risk	12 Months Ended
	Dec. 31, 2017 customer item	Dec. 31, 2016	Dec. 31, 2015
Top ten customers
Financial risk factors
Largest customers \| customer	10
Total revenues	36.00%	33.00%	32.00%
Minimum
Financial risk factors
Credit rating agencies \| item	2