Property And Equipment, Net (Schedule Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Proved oil and gas properties	$ 2,207,220	$ 1,713,827
Accumulated depreciation, depletion and amortization	(711,239)	(561,279)
Proved oil and gas properties, net	1,495,981	1,152,548
Unproved properties, not being amortized
Unevaluated leasehold and seismic costs	302,391	238,833
Exploratory wells in progress	41,926	43,803
Capitalized interest	50,974	41,052
Total unproved properties, not being amortized	395,291	323,688
Other property and equipment	16,323	17,079
Accumulated depreciation	(6,523)	(5,641)
Other property and equipment, net	9,800	11,438
TOTAL PROPERTY AND EQUIPMENT, NET	$ 1,901,072	$ 1,487,674