Derivative Instruments And Hedging Activities Location of Gain Loss in Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	$ 28,599	$ (16,695)
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	33,592	(14,994)
Operating Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	$ (4,993)	$ (1,701)