Financial Risk and Fair Value Disclosures - Details of Forward Exchange Contracts (Detail) - Forward exchange contracts [member] $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Disclosure of detailed information about financial instruments [line items]
Notional Amount on sale of foreign currency	$ 28
Contract Period, beginning date	Dec. 10, 2018
Contract Period, end date	Jan. 07, 2019

The nominal or face amount of a financial instrument, used to calculate payments made on that instrument.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_NotionalAmount
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant