Fair Value Measurements and Derivative Instruments - Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Asset Derivatives
Asset Derivatives	$ 57,937		$ 188,576
Liability Derivatives
Liability Derivatives	275,036		100,260
Designated as Hedging Instrument
Asset Derivatives
Asset Derivatives	45,966	[1]	173,229	[1]
Liability Derivatives
Liability Derivatives	252,678	[1]	77,629	[1]
Designated as Hedging Instrument | Foreign currency collar options | Other assets
Asset Derivatives
Asset Derivatives	0	[1]	22,172	[1]
Designated as Hedging Instrument | Foreign currency collar options | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	0	[1]	0	[1]
Not Designated as Hedging Instrument
Asset Derivatives
Asset Derivatives	11,971		15,347
Liability Derivatives
Liability Derivatives	22,358		22,631
Interest rate swaps | Designated as Hedging Instrument | Other assets
Asset Derivatives
Asset Derivatives	2,384	[1]	56,571	[1]
Interest rate swaps | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	50,688	[1]	66,920	[1]
Foreign currency forward contracts | Designated as Hedging Instrument | Other assets
Asset Derivatives
Asset Derivatives	40,682	[1]	13,783	[1]
Foreign currency forward contracts | Designated as Hedging Instrument | Derivative financial instruments
Asset Derivatives
Asset Derivatives	2,882	[1]	61,596	[1]
Foreign currency forward contracts | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	99,437	[1]	0	[1]
Foreign currency forward contracts | Designated as Hedging Instrument | Accrued expenses and other liabilities
Liability Derivatives
Liability Derivatives	29,304	[1]	0	[1]
Foreign currency forward contracts | Not Designated as Hedging Instrument | Derivative financial instruments
Asset Derivatives
Asset Derivatives	11,971		15,347
Foreign currency forward contracts | Not Designated as Hedging Instrument | Accrued expenses and other liabilities
Liability Derivatives
Liability Derivatives	22,358		22,631
Foreign currency collar options | Designated as Hedging Instrument | Derivative financial instruments
Asset Derivatives
Asset Derivatives	0	[1]	0	[1]
Foreign currency collar options | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	8,465	[1]	0	[1]
Fuel swaps | Designated as Hedging Instrument | Swaps | Other assets
Asset Derivatives
Asset Derivatives	18	[1]	8,205	[1]
Fuel swaps | Designated as Hedging Instrument | Swaps | Derivative financial instruments
Asset Derivatives
Asset Derivatives	0	[1]	10,902	[1]
Fuel swaps | Designated as Hedging Instrument | Swaps | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	27,016	[1]	9,052	[1]
Fuel swaps | Designated as Hedging Instrument | Swaps | Accrued expenses and other liabilities
Liability Derivatives
Liability Derivatives	$ 37,768	[1]	$ 1,657	[1]

[1] Accounting Standard Codification 815-20 “Derivatives and Hedging.”