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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ 89	$ 2,155	$ 1,758	$ 2,223
Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives				(73)
Other comprehensive income | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	(257)	1,753	806	2,304
Other comprehensive income | Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives				(218)
Cost of sales | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	328	391	1,003	(214)
Cost of sales | Commodity Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives				145
Selling, general and administrative expense | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives				75
Foreign currency gain (loss) | Foreign Currency Derivatives
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivatives	$ 18	$ 11	$ (51)	$ 58