Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Parenthetical) (Detail) - Designated As Hedging Instrument [Member] - Unrealized Gain (Loss) on Cash Flow Hedges [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Cost of revenues [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ 18	$ (14)	$ 11	$ (73)
Operating Expenses [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ 88	$ (99)	$ 3	$ (611)