Financial risk management - Credit risk (Details) - CREDIT RISK EXPOSURE - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
CREDIT RISK EXPOSURE
Maximum exposure to credit risk	$ 263.4	$ 107.1
Cash and cash equivalents
CREDIT RISK EXPOSURE
Maximum exposure to credit risk	186.3	83.4
Trade and other receivables
CREDIT RISK EXPOSURE
Maximum exposure to credit risk	$ 77.1	$ 23.7

The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
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-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 36
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_36_a&doctype=Standard&book=b
-URIDate 2020-01-01

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