Information Related to Effect of Derivative Instruments on Our Consolidated Condensed Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ (1,021)	$ (3,884)	$ (354)	$ 1,632
Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(18)	(373)	34	(421)
Other Comprehensive Income (Loss) | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(868)	(460)	(624)	(1,237)
Other Comprehensive Income (Loss) | Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	139	(373)	544	(421)
Revaluation of Derivatives | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives		(2,526)		3,752
Revaluation of Derivatives | Currency Related Interest Rate Swap
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives		2,392		(4,903)
Cost of Sales | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(112)	(694)	23	(1,014)
Cost of Sales | Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(157)		(510)
Selling, general and administrative expense | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives		(235)	139	(189)
Foreign Currency (Loss) Gain | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ (41)	$ 31	$ 108	$ 320