Fair Value Measurements (Reconciliations Of Level 3 Fair Value Measurements) (Details) (Collar [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Collar [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Beginning of period	$ 3,355		$ (2,595)
Included in earnings	777	[1]	(3,428)	[1]
Settlements	(3,275)		1,559
End of period	857		(4,464)
Total losses for the period included in earnings attributable to the change in unrealized loss relating to assets still held at end of period	$ (2,498)		$ (1,869)

[1] Commodity collars are reported in the Unaudited Condensed Consolidated Statements of Operations in gain (loss) on derivatives not designated as hedges.