Property, Plant And Equipment (Property, Plant And Equipment) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Property, Plant And Equipment [Abstract]
Subject to depletion	$ 5,049,640	$ 4,805,161
Unevaluated costs	460,158	304,269
Accumulated depletion	(2,440,846)	(2,274,785)
Net oil and gas properties	3,068,952	2,834,645
Pipelines and processing facilities	355,201	235,676
General properties	73,530	70,267
Accumulated depreciation	(120,878)	(72,743)
Net other plant and equipment	307,853	233,200
Property, plant and equipment - net	$ 3,376,805	$ 3,067,845