Accrued Severance Benefits - Changes in Accrued Severance Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Accrued severance benefits, net	$ 139,289	$ 134,172
Employee severance [Member]
Restructuring Cost and Reserve [Line Items]
Beginning balance	135,356	116,036
Provisions	17,703	23,169
Severance payments	(6,650)	(6,130)
Translation adjustments	(6,003)	2,281
Ending balance	140,405	135,356
Less: cumulative contributions to the National Pension Fund	(346)	(383)
Group severance insurance plan	(770)	(801)
Accrued severance benefits, net	$ 139,289	$ 134,172

Cumulative contributions to national pension fund.

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- Definition

Group severance insurance plan.

+ References

No definition available.

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- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

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- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

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- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount of foreign currency translation adjustment increasing or decreasing the accrual for a specified type of restructuring cost.

+ References

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

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- Definition

Liability for amount due employees, in addition to wages and any other money that employers owe employees, when their employment ends through a layoff or other termination. For example, a company may provide involuntarily terminated employees with a lump sum payment equal to one week's salary for every year of employment.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Postemployment Benefits

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