Property And Equipment, Net (Schedule Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Property And Equipment, Net [Abstract]
Proved oil and gas properties	$ 1,496,489	$ 1,305,084
Accumulated depreciation, depletion and amortization	(428,848)	(397,737)
Proved oil and gas properties, net	1,067,641	907,347
Unevaluated leasehold and seismic costs	291,424	277,425
Capitalized interest	50,998	46,471
Exploratory wells in progress	64,447	70,533
Total costs not subject to amortization	406,869	394,429
Other property and equipment	15,235	12,835
Accumulated depreciation	(4,426)	(4,097)
Other property and equipment, net	10,809	8,738
TOTAL PROPERTY AND EQUIPMENT, NET	$ 1,485,319	$ 1,310,514