Foreign Currency Gain (Loss), Net - Additional Information (Detail) $ in Thousands |
Dec. 31, 2016
USD ($)
₩ / $
|
Dec. 31, 2015
USD ($)
₩ / $
|
Dec. 31, 2014
USD ($)
₩ / $
|
|---|---|---|---|
| Foreign Currency Transaction [Abstract] | |||
| Exchange rates using first base rate | ₩ / $ | 1,208.5 | 1,172.0 | 1,099.2 |
| Intercompany loan balances | $ | $ 598,212 | $ 591,388 | $ 765,265 |