Foreign Currency Gain (Loss), Net - Additional Information (Detail) $ in Millions |
Sep. 30, 2016
USD ($)
₩ / $
|
Dec. 31, 2015
₩ / $
|
|---|---|---|
| Foreign Currency Transaction [Abstract] | ||
| Exchange rates using first base rate | ₩ / $ | 1,096.3 | 1,172.0 |
| Intercompany loan balance | $ | $ 591 |