Asset Retirement Obligations (Schedule Of Asset Retirement Obligations) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
ARO liability, January 1:	$ 146,159		$ 96,446
Accretion of discount	5,450		4,615
Liability incurred	4,857		56,650	[1]
Liability settled	(4,751)		(2,788)
Liability sold	(2,622)		(1,258)
Revision of estimates	(15,436)	[2]	(7,506)	[2]
ARO liability, December 31:	133,657		146,159
Less current portion	2,954		2,953
Total long-term ARO liability	130,703		143,206
Noble Energy, Inc. [Member]
Liability incurred			$ 46,700

[1] The liability incurred increased $46.7 million related to the Noble properties acquired in September 2012.

[2] Plugging liability estimates were revised in both 2013 and 2012 for updates in the cost of services used to plug wells over the preceding year. We had various upward and downward adjustments as well as changes in estimated timing of cash flows.