Property And Equipment, Net (Schedule Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Proved properties	$ 2,747,915	$ 2,182,226
Accumulated depreciation, depletion and amortization	(1,000,070)	(773,742)
Proved properties, net	1,747,845	1,408,484
Unproved properties, not being amortized
Unevaluated leasehold and seismic costs	388,169	302,232
Exploratory wells in progress	49,171	30,196
Capitalized interest	62,382	45,009
Total unproved properties, not being amortized	499,722	377,437
Other property and equipment	15,855	15,260
Accumulated depreciation	(8,275)	(6,966)
Other property and equipment, net	7,580	8,294
Total property and equipment, net	$ 2,255,147	$ 1,794,215