Derivative Financial Instruments - Impact of Derivative Instruments on Consolidated Statement of Operations (Detail) (Derivatives in ASC 815 Cash Flow Hedging Relationships [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (69)	$ 7,497
Other income (expenses) - Others [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	(12)	634
Net sales [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Statement of Operations (Effective Portion)	6,033	2,984
Forward [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)		3,405
Forward [Member] | Other income (expenses) - Others [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)		412
Forward [Member] | Net sales [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Statement of Operations (Effective Portion)		3,484
Zero cost collars [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	(69)	4,092
Zero cost collars [Member] | Other income (expenses) - Others [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	(12)	222
Zero cost collars [Member] | Net sales [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Statement of Operations (Effective Portion)	$ 6,033	$ (500)