Derivative Instruments - Location and Fair Value of Foreign Currency Sales Contracts Recorded on Condensed Consolidated Balance Sheets (Detail) - Foreign Currency Sales Contracts [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Receivables [Member]
Derivative [Line Items]
Fair value hedged items	$ (470)	$ (269)
Other Current Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	1,412	961
Fair value hedged items	135	169
Other Noncurrent Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	22	0
Fair value hedged items	7	16
Other Current Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	59	89
Fair value hedged items	1,152	907
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	1	1
Fair value hedged items	$ 14	$ 0