Leases - Additional Information (Detail) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) Aircraft	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Disclosure of finance and operating lease by lessee [Line Items]
Weighted average incremental borrowing rate	3.37%	3.37%
Average duration of long-term lease agreement	10 years
Number of aircraft under lessor \| Aircraft	2
Carrying amount of aircraft under operating lease	$ 12.3	$ 37.7
Scheduled expiration date of lease	2022
Total lease income amounts	$ 3.2	3.5	$ 3.5
Total liability related to leases including the provision of dismantling	$ 255.5	$ 328.9

The weighted average lessee's incremental borrowing rate applied to lease liabilities recognised in the statement of financial position at the date of initial application of IFRS 16. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow over a similar term, and with a similar security, the funds necessary to obtain an asset of a similar value to the right-of-use asset in a similar economic environment.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph C12
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_C12_a&doctype=Appendix&subtype=C
-URIDate 2020-01-01

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Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant