Derivatives (Amount Of Gain Or (Loss) Recognized In Accumulated OCI On Derivative) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)	$ 30,314	[1]	$ (3,163)	[1]
Commodity Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)	$ 30,314	[1]	$ (3,163)	[1]

[1] Net of taxes.