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Borrowings - Summary of Long-term Borrowings (Detail) $ in Thousands, ₩ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2018 KRW (₩) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 KRW (₩) | Dec. 31, 2017 USD ($) | Jan. 01, 2017 KRW (₩)
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Borrowings | ₩ 6,648,293 |  | ₩ 6,683,662 |  |
Total | ₩ 5,279,812 |  | 5,110,188 |  | ₩ 6,300,790
Shinhan Bank [member] | Vessel facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates adjustment rate | 2.808% | 2.808% |  |  |
Kookmin Bank [member] | Vessel facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates adjustment rate | 2.808% | 2.808% |  |  |
Long-term borrowings [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Borrowings | ₩ 546,090 |  | 587,133 |  |
Less: Current portion | (394,927) |  | (87,398) |  |
Total | 151,163 |  | 499,735 |  |
Long-term borrowings [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Borrowings | ₩ 30,000 |  | 30,000 |  |
Long-term borrowings [member] | Export-Import Bank of Korea [member] | Inter-Korean Cooperation Fund [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 1.50% | 1.50% |  |  |
Borrowings | ₩ 3,948 |  | 4,688 |  |
Long-term borrowings [member] | Shinhan Bank [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 2.93% | 2.93% |  |  |
Borrowings | ₩ 5,000 |  | 30,000 |  |
Long-term borrowings [member] | Shinhan Bank [member] | Facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.01% | 3.01% |  |  |
Borrowings | ₩ 30,000 |  | 6,000 |  |
Long-term borrowings [member] | Shinhan Bank [member] | Vessel facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates description | LIBOR (3M)+0.706% |  |  |  |
Annual interest rates adjustment rate | 0.706% | 0.706% |  |  |
Borrowings | ₩ 10,063 | $ 9,000 | 16,071 | $ 15,000 |
Long-term borrowings [member] | KEB Hana Bank [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.95% | 3.95% |  |  |
Borrowings |  |  | 3,000 |  |
Long-term borrowings [member] | Standard Charted Bank [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.16% | 3.16% |  |  |
Borrowings | ₩ 6,000 |  | 8,000 |  |
Long-term borrowings [member] | NongHyup Bank [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 2.86% | 2.86% |  |  |
Borrowings | ₩ 8,000 |  | 8,000 |  |
Long-term borrowings [member] | NongHyup Bank [member] | Facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 2.00% | 2.00% |  |  |
Borrowings | ₩ 104 |  | 123 |  |
Long-term borrowings [member] | Korea Development Bank [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.30% | 3.30% |  |  |
Long-term borrowings [member] | Korea Development Bank [member] | General loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.02% | 3.02% |  |  |
Borrowings | ₩ 10,000 |  |  |  |
Long-term borrowings [member] | Kookmin Bank [member] | Facility loans [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 2.59% | 2.59% |  |  |
Borrowings |  |  | 2,333 |  |
Long-term borrowings [member] | NH Investment & Security Co., Ltd. [member] | Commercial papers [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 3.17% | 3.17% |  |  |
Borrowings | ₩ 300,000 |  | 300,000 |  |
Long-term borrowings [member] | Other Financial Instruments [member] | Redeemable convertible preferred stock [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 1.00% | 1.00% |  |  |
Borrowings | ₩ 950 |  | 950 |  |
Long-term borrowings [member] | Other Financial Instruments [member] | Kookmin Bank and other [member] |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Annual interest rates | 4.59% | 4.59% |  |  |
Borrowings | ₩ 142,025 | $ 127,023 | ₩ 177,968 | $ 166,108 |

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