Supplemental Oil And Gas Disclosures (Standardized Measure Of Discounted Future Cash Flows Relating To Proved Reserves Disclosure) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Oil and Gas Disclosures [Abstract]
Future net cash flows relating to proved oil and gas reserves future cash inflows	$ 5,573,119	$ 4,522,351	$ 4,583,629
Future production costs	(1,734,985)	(1,405,773)	(1,277,856)
Future development costs	(571,170)	(431,673)	(340,992)
Future income tax expenses	(1,044,608)	(762,519)	(952,736)
Future net cash flows	2,222,356	1,922,386	2,012,045
10% annual discount for estimated timing of cash flows	(996,380)	(842,430)	(924,136)
Standardized measure of discounted future net cash flows relating to proved oil, NGLs and natural gas reserves	$ 1,225,976	$ 1,079,956	$ 1,087,909
Percentage of annual discount for estimated timing of cash flows	10.00%	10.00%	10.00%