Information Related to Effect of Derivative Instruments on Our Consolidated Condensed Statements of Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ 5,950	$ (231)
Other Comprehensive Income (Loss) | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(347)	61
Other Comprehensive Income (Loss) | Interest Rate Swap
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives		39
Other Comprehensive Income (Loss) | Commodity derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	76
Revaluation of Derivatives | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	6,197	262
Revaluation of Derivatives | Currency Related Swap
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(7,161)	(509)
Cost of Sales | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(128)	(53)
Selling, General and Administrative Expense | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	21	(48)
Foreign Currency Gain (Loss) | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ 207	$ (453)