Taxation - Additional Information (Detail)	6 Months Ended	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Disclosure Of Income Taxes [line items]
Effective tax rate on reported (loss)/profit before taxation	(0.80%)	25.50%	22.60%

The tax expense (income) divided by the accounting profit. [Refer: Accounting profit]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2019-01-01
-Paragraph 81
-Subparagraph c
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_81_c_ii&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_AverageEffectiveTaxRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration