Fair Value and Line Item Caption of Derivative Instruments (Detail) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
Asset Derivatives
Asset Derivatives	$ 447,469		$ 195,944
Liability Derivatives
Liability Derivatives	2,038		88,491
Designated as Hedging Instrument
Asset Derivatives
Asset Derivatives	415,025	[1]	164,231	[1]
Liability Derivatives
Liability Derivatives	2,038	[1]	88,491	[1]
Designated as Hedging Instrument | Cross currency swaps | Other Assets
Asset Derivatives
Asset Derivatives	51,595	[1]	13,017	[1]
Designated as Hedging Instrument | Foreign currency forward contracts | Other Assets
Asset Derivatives
Asset Derivatives	69,941	[1]	8,058	[1]
Designated as Hedging Instrument | Foreign currency forward contracts | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives	13,645	[1]
Designated as Hedging Instrument | Foreign currency forward contracts | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	607	[1]	19,630	[1]
Designated as Hedging Instrument | Foreign currency forward contracts | Accrued expenses and other liabilities
Liability Derivatives
Liability Derivatives	644	[1]	68,374	[1]
Interest rate swaps | Designated as Hedging Instrument | Other Assets
Asset Derivatives
Asset Derivatives	57,871	[1]	56,497	[1]
Fuel swaps | Designated as Hedging Instrument | Other Assets
Asset Derivatives
Asset Derivatives	104,783	[1]	37,362	[1]
Fuel swaps | Designated as Hedging Instrument | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives	117,190	[1]	49,297	[1]
Fuel swaps | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	787	[1]	487	[1]
Not Designated as Hedging Instrument
Asset Derivatives
Asset Derivatives	32,444		31,713
Not Designated as Hedging Instrument | Fuel call options | Other Assets
Asset Derivatives
Asset Derivatives	27,925		24,519
Not Designated as Hedging Instrument | Fuel call options | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives			7,194
Not Designated as Hedging Instrument | Foreign currency forward contracts | Other Assets
Asset Derivatives
Asset Derivatives	$ 4,519

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