Hedging Cash Flow Hedging Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Total	$ (1,371)		$ (22,947)		$ (5,772)		$ 20,493
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Total	3,069	[1]	11,568	[1]	17,103	[1]	30,029	[1]
Gain (loss) recognized in income on derivative (ineffective portion) - Total	342	[1]	13,089	[1]	(211)	[1]	12,839	[1]
Foreign currency derivatives [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Currency Hedge Portfolio	(13,580)		9,075		(17,755)		7,921
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Currency hedge portfolio	(753)	[1]	1,093	[1]	3,628	[1]	1,886	[1]
Gain (loss) recognized in income on derivative (ineffective portion) - Currency Hedge Portfolio	0	[1]	0	[1]	0	[1]	0	[1]
Bunker fuel forward contracts [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI on derivative (effective portion) - Bunker Fuel Forward Contracts	12,209		(32,022)		11,983		12,572
Gain (loss) reclassified from accumulated OCI into income (effective portion) - Bunker Fuel Forward Contracts	3,822	[1]	10,475	[1]	13,475	[1]	28,143	[1]
Gain (loss) recognized in income on derivative (ineffective portion) - Bunker Fuel Forward Contracts	$ 342	[1]	$ 13,089	[1]	$ (211)	[1]	$ 12,839	[1]

[1] 1 Both the gain (loss) reclassified from accumulated OCI into income (effective portion) and the gain (loss) recognized in income on derivative (ineffective portion), if any, are included in "Net sales" for the currency hedge portfolio and "Cost of sales" for bunker fuel forward contracts.