Fair Value Measurements and Derivative Instruments (Details 11) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives			$ (8,634)	$ 3,052
Other income (expense)
Derivative Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	16,971	5,480	(10,224)	744
Foreign exchange contracts | Other income (expense)
Derivative Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	16,789	4,793	(10,491)	9,290
Fuel contracts | Fuel swaps | Other income (expense)
Derivative Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	220	(1,112)	268	(2,875)
Fuel contracts | Options | Other income (expense)
Derivative Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (38)	$ 1,799	$ (1)	$ (5,671)