The adjustment to the basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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.

+ References

No definition available.

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- Definition

The number of shares issued by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-IssueDate 2017-01-01
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- Definition

The nominal value per share.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Long term debt repayment description.

+ References

No definition available.

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Borrowings - Summary of Long-term Borrowings (Parenthetical) (Detail) - ₩ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2010
Inter-Korean Cooperation Fund [Member]
Disclosure of detailed information about borrowings [Line Items]
Long term debt repayment	The Inter-Korean Cooperation Fund is repayable in installments over 13 years after a seven-year grace period.
Vessel facility loans [member] \| Shinhan Bank [Member]
Disclosure of detailed information about borrowings [Line Items]
LIBOR rate	1.695%
Vessel facility loans [member] \| Kookmin Bank [member]
Disclosure of detailed information about borrowings [Line Items]
LIBOR rate	1.695%
Redeemable convertible preferred stock [member]
Disclosure of detailed information about borrowings [Line Items]
Shares issued		1,900,000
Par value per share		₩ 500