Other assets - Narrative (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Subclassifications of assets, liabilities and equities [abstract]
Restricted cash and cash equivalents for vessels under construction	$ 66,452,000	$ 0
Other current assets	$ 60,931,000	$ 0

The amount in the consolidated financial statements of the assets of the group to which significant restrictions (for example, statutory, contractual and regulatory restrictions) apply on the entity's ability to access or use the assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph 13
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_13_c&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_AssetsToWhichSignificantRestrictionsApply
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant