Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Consolidated Statement of Operations (Parenthetical) (Detail) - Designated As Hedging Instrument [Member] - Unrealized Gain (Loss) on Cash Flow Hedges [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cost of revenues [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ (8)	$ (107)	$ (72)
Operating Expenses [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ (82)	$ (865)	$ (581)