Acquisitions (Summary Of Fair Value Of Assets Acquired And Liabilities Assumed For 2013 East Texas Acquisition) (Details) (2013 East Texas Properties [Member], USD $) In Thousands, unless otherwise specified	Aug. 06, 2013
2013 East Texas Properties [Member]
Business Acquisition [Line Items]
Oil and gas properties	$ 105,751
Investment in ETSWDC	9,576
Asset retirement obligation	(6,069)
Other current liabilities	(1,044)
Net assets (liabilities) acquired	$ 108,214