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, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating Expenses [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge loss reclassified	$ (19)	$ 525	$ (31)	$ 1,069
Cost of Revenues [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge loss reclassified	$ (2)	$ 36	$ (3)	$ 75