Derivative Instruments - Summary of Amount Recognized as and Reclassified from Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss) Beginning of the Year	$ 215	$ 620	$ 739	$ 551
Plus Recognized as Comprehensive Income (Loss)	(6)	15	(321)	239
Less Gain Reclassified from Accumulated Other Comprehensive Loss	92	167	301	322
Accumulated Other Comprehensive Income (Loss) End of the Period	117	468	117	468
Foreign Currency Purchase Contracts [Member]
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss) Beginning of the Year	232	209	239	216
Plus Recognized as Comprehensive Income (Loss)	0	0	0	0
Less Gain Reclassified from Accumulated Other Comprehensive Loss	2	6	9	13
Accumulated Other Comprehensive Income (Loss) End of the Period	230	203	230	203
Futures Contracts - Copper and Aluminum [Member]
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss) Beginning of the Year	(17)	411	500	335
Plus Recognized as Comprehensive Income (Loss)	(6)	15	(321)	239
Less Gain Reclassified from Accumulated Other Comprehensive Loss	90	161	292	309
Accumulated Other Comprehensive Income (Loss) End of the Period	$ (113)	$ 265	$ (113)	$ 265