Currency Transaction Gains (Losses) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	$ 46,887	$ 37,572	$ 63,519
Operating income
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	44,060	38,842	61,956
Other non-operating income (expense), net
Currency Transaction Gains (Losses) [Line Items]
Net transaction gains (losses)	$ 2,827	$ (1,270)	$ 1,563