Operating segments - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of major customers [line items]
Revenue	$ 96,586	$ 121,288
Individual customer
Disclosure of major customers [line items]
Revenue	26,587	31,080
Individual customer
Disclosure of major customers [line items]
Revenue	$ 17,547	30,555
Individual customer
Disclosure of major customers [line items]
Revenue		$ 17,989

The amount of revenue from contracts with customers. A customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. [Refer: Revenue]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2018-01-01
-Name IFRS
-Number 15
-IssueDate 2017-01-01
-Paragraph 113
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=15&date=2017-03-01&anchor=para_113_a&doctype=Standard
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2018-01-01
-Name IFRS
-Number 15
-IssueDate 2017-01-01
-Paragraph 114
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=15&date=2017-03-01&anchor=para_114&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_RevenueFromContractsWithCustomers
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration