Trade and Other Receivables - Additional Information (Detail)	12 Months Ended
Dec. 31, 2017
Bottom of Range [Member]
Disclosure Of Financial Assets [Line Items]
Trade receivable settlement terms	30 days
Top of Range [Member]
Disclosure Of Financial Assets [Line Items]
Trade receivable settlement terms	180 days

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration