Derivative Financial Instruments - Effects of Derivative Instruments on Financial Statements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of income/(loss) recognized in other comprehensive income (loss)	$ 441	$ (55,563)	$ 12,799	$ (71,013)
Cost of operations [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Income (loss) reclassified from AOCI into income: effective portion	293	(2,845)	495	(831)
Gain on foreign currency-net [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss recognized in income: ineffective portion and amount excluded from effectiveness testing	$ 3,381	$ 7,291	$ 4,228	$ 4,442