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	Jun. 30, 2018	Dec. 31, 2017
Receivables [Member]
Derivative [Line Items]
Fair value hedged items	$ 326	$ (269)
Other Current Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	61	961
Fair value hedged items	502	169
Other Noncurrent Assets [Member]
Derivative [Line Items]
Fair value hedge contracts	0	0
Fair value hedged items	77	16
Other Current Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	703	89
Fair value hedged items	116	907
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Fair value hedge contracts	45	1
Fair value hedged items	$ 0	$ 0