Events after the reporting period - Dividends declared (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 30, 2021	Jan. 01, 2021
Events after the reporting period
Dividends declared	$ 46,000	$ 50
Dividends declared per share	$ 2,300	$ 2,500

The amount of dividends proposed or declared after the reporting period but before financial statements are authorised for issue. Such dividends are not recognised as a liability at the end of the reporting period because no obligation exists at that time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 137
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_137_a&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 10
-IssueDate 2020-01-01
-Paragraph 13
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=10&code=ifrs-tx-2020-en-r&anchor=para_13&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration