Supplemental Information On Oil And Gas Exploration And Production Activities (Unaudited) - Schedule Of Standardized Measure (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Extractive Industries [Abstract]
Future cash inflows	$ 481,131	$ 1,464,138	$ 718,049
Future production costs	(192,349)	(427,113)	(202,957)
Future development costs	(91,725)	(312,010)	(220,828)
Future income tax expense		(180,248)
Future net cash flows	197,057	544,767	294,264
10% annual discount for estimated timing of cash flows	(92,661)	(288,911)	(168,907)
Standardized measure of discounted future cash flows	$ 104,396	$ 255,856	$ 125,357	$ 25,132