Derivative Instruments And Hedging Activities Location of Gain Loss in Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	$ 1,531	$ 52,406	$ 30,130	$ 35,711
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	1,839	50,863	35,431	35,869
Operating Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	$ (308)	$ 1,543	$ (5,301)	$ (158)