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Financial Risk Management - Summary of Exposures to Risks, Effects on Profit before Income Tax and Shareholders' Equity (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
10% strengthening in foreign exchange rate [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of foreign exchange rate | 10.00% | 10.00% | 10.00%
Income before tax | ₩ (51,581) | ₩ (2,350) | ₩ (10,132)
Shareholders' equity | ₩ (44,638) | ₩ 633 | ₩ (7,273)
10% weakening in foreign exchange rate [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of foreign exchange rate | (10.00%) | (10.00%) | (10.00%)
Income before tax | ₩ 51,581 | ₩ (2,851) | ₩ 10,132
Shareholders' equity | ₩ 44,638 | ₩ (62) | ₩ 7,273
Ten percentage increase in market equity price [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of price | 10.00% | 10.00% | 10.00%
Income before tax | ₩ 23 | ₩ 12 |
Shareholders' equity | ₩ 697 | ₩ 898 | ₩ 686
10% decrease in market equity price [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of price | (10.00%) | (10.00%) | (10.00%)
Income before tax | ₩ (23) | ₩ (12) |
Shareholders' equity | ₩ (697) | ₩ (898) | ₩ (686)
100 basis point increase in market interest rate [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of interest rate | 1.00% | 1.00% | 1.00%
Income before tax | ₩ 425 | ₩ 1,059 | ₩ 1,942
Shareholders' equity | ₩ 14,764 | ₩ 9,689 | ₩ 4,868
100 basis point decrease in market interest rate [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Fluctuation of interest rate | 1.00% | 1.00% | 1.00%
Income before tax | ₩ (482) | ₩ (1,958) | ₩ (1,954)
Shareholders' equity | ₩ (19,280) | ₩ (10,237) | ₩ (5,198)

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