Currency Transaction Gains (Losses) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	$ 17,610	$ 13,484	$ 32,477	$ 26,677
Operating income
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	13,881	13,260	29,672	27,375
Other non-operating income (expense), net
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	$ 3,729	$ 224	$ 2,805	$ (698)