Derivatives And Fair Value Measurements (Changes In Level 3 Fair Values) (Details) (Fair Value Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	$ 13,434	$ (556)	$ 31,317	$ (538)
Balance at beginning of period	7,201	(9,037)	23,485	(4,931)
Balance at end of period	(5,533)	(9,873)	(5,533)	(9,873)
Total gains (losses) included in net derivative gains (losses) attributable to the change in unrealized gains (losses) related to assets still held at the reporting date	(11,385)	2,854	(26,961)	2,762
Derivative gains (losses) [Member]
Settlements	$ 700	$ (1,392)	$ 2,299	$ (5,480)