Hedging Cash Flow Hedging Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Total	$ 9,062	$ 17,789
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Total	(5,793)	9,895
Gain (loss) recognized in income on derivative (ineffective portion) - Total	(610)	830
Foreign currency derivatives [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Currency Hedge Portfolio	6,564	(851)
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Currency hedge portfolio	(8,632)	4,381
Gain (loss) recognized in income on derivative (ineffective portion) - Currency Hedge Portfolio	0	0
Bunker fuel forward contracts [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Bunker Fuel Forward Contracts	2,498	18,640
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Bunker Fuel Forward Contracts	2,839	5,514
Gain (loss) recognized in income on derivative (ineffective portion) - Bunker Fuel Forward Contracts	$ (610)	$ 830

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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The amount of net gains or losses on foreign currency cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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The net gain (loss) during the reporting period due to ineffectiveness in foreign currency cash flow hedges. Recognized in earnings.

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The net gain (loss) recognized in earnings during the period due to ineffectiveness in price risk cash flow hedges.

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The amount of net gains or losses on price risk cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income.

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Amount of net unrealized gain (loss) related to the change in fair value of foreign currency exchange rate derivatives designated as cash flow hedging instruments. Recorded in accumulated other comprehensive income to the extent that the cash flow hedge is determined to be effective.

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Amount of unrealized gain (loss) arising from the change in fair value of price risk derivatives designated as cash flow hedging instruments recorded in accumulated other comprehensive income in the period, before taxes, to the extent that the cash flow hedge is determined to be effective.

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