Derivative Financial Instruments - Effects of Derivative Instruments on Financial Statements (Detail) - Derivatives Designated as Hedges [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (28,248)	$ (39,563)	$ (56,904)	$ (26,764)
Cost of operations [Member]
Derivative Instruments Gain Loss [Line Items]
Income (loss) reclassified from AOCI into income: effective portion	27,547	6,788	66,973	7,283
Gain (loss) on foreign currency-net [Member]
Derivative Instruments Gain Loss [Line Items]
Gain(loss) recognized in income (loss): ineffective portion and amount excluded from effectiveness testing	$ (1,329)	$ (386)	$ 2,535	$ 3,842