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	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (1,417)	$ 8,002	$ (1,417)	$ 6,201
Other income, net [Member]
Derivative [Line Items]
Amount of Loss Recognized in Statement of Operations on Derivatives (Ineffective Portion)	(306)	(36)	(306)	(52)
Net sales [Member]
Derivative [Line Items]
Amount of Gain Reclassified from AOCI into Statement of Operations (Effective Portion)		2,647	485	2,644
Zero cost collars [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	(1,417)	8,002	(1,417)	6,201
Zero cost collars [Member] | Other income, net [Member]
Derivative [Line Items]
Amount of Loss Recognized in Statement of Operations on Derivatives (Ineffective Portion)	$ (306)	(36)	(306)	(52)
Zero cost collars [Member] | Net sales [Member]
Derivative [Line Items]
Amount of Gain Reclassified from AOCI into Statement of Operations (Effective Portion)		$ 2,647	$ 485	$ 2,644