Derivative Instruments - Location and Fair Value of Foreign Currency Sales Contracts Recorded on Consolidated Balance Sheets (Detail) - Foreign Currency Sales Contracts [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Member]
Derivative [Line Items]
Fair value hedged item	$ (269)	$ 121
Other Current Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	961	214
Fair value hedged item	169	808
Other Noncurrent Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	0	2
Fair value hedged item	16	45
Other Current Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	89	940
Fair value hedged item	907	233
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	1	35
Fair value hedged item	$ 0	$ 5