Inventories - Additional Information (Detail) - KRW (₩)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Inventories [line items]
Reversals of inventory write-downs	₩ 0	₩ 0	₩ 0
Inventories recognized as operating expenses	2,509,000,000	6,079,000,000	₩ 3,751,000,000
Cost of goods sold [member]
Inventories [line items]
Inventories recognized as operating expenses	₩ 1,411,986,000,000	₩ 1,498,087,000,000

The amount recognised as a reduction in the amount of inventories recognised as an expense due to the reversal of any write-down of inventories resulting from an increase in net realisable value. [Refer: Inventories; Inventory write-down]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 2
-IssueDate 2018-01-01
-Paragraph 36
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2018-03-01&anchor=para_36_f&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 98
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_98_a&doctype=Standard
-URIDate 2018-03-16

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration