Company's Financial Instruments Recorded at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Assets:
Derivative financial instruments	$ 201,130	[1]	$ 195,944	[1]
Investments	6,941	[2]	7,974	[2]
Total Assets	208,071		203,918
Liabilities:
Derivative financial instruments	84,344	[3]	88,491	[3]
Total Liabilities	84,344		88,491
Level 1
Assets:
Investments	6,941	[2],[4]	7,974	[2],[4]
Total Assets	6,941	[4]	7,974	[4]
Level 2
Assets:
Derivative financial instruments	201,130	[1],[5]	195,944	[1],[5]
Total Assets	201,130	[5]	195,944	[5]
Liabilities:
Derivative financial instruments	84,344	[3],[5]	88,491	[3],[5]
Total Liabilities	$ 84,344	[5]	$ 88,491	[5]

[1] Consists of foreign currency forward contracts, interest rate, cross currency, fuel swaps and fuel call options. Please refer to the "Fair Value of Derivative Instruments" table for breakdown by instrument type.

[2] Consists of exchange-traded equity securities and mutual funds.

[3] Consists of interest rate and fuel swaps and foreign currency forward contracts. Please refer to the "Fair Value of Derivative Instruments" table for breakdown by instrument type.

[4] Inputs based on quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Valuation of these items does not entail a significant amount of judgment.

[5] Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. For foreign currency forward contracts, interest rate, cross currency and fuel swaps, fair value is derived using valuation models that utilize the income valuation approach. These valuation models take into account the contract terms such as maturity, as well as other inputs such as exchange rates, fuel types, fuel curves, interest rate yield curves, creditworthiness of the counterparty and the Company. For fuel call options, fair value is estimated by using the prevailing market price for the instruments consisting of published price quotes for similar assets based on recent transactions in an active market.