Exploratory Well Costs (Tables)

12 Months Ended

Dec. 31, 2011

Exploratory Well Costs [Abstract]

Capitalized Exploratory Well And Project Activity

	Year Ended December 31,
	2011			2010			2009
	(in thousands)
Beginning capitalized exploratory well costs	$	96,193		$	127,574		$	124,014
Additions to exploratory well costs pending the determination of proved reserves		524,313			238,905			80,222
Reclassification due to determination of proved reserves		(480,716	)		(160,879	)		(58,792	)
Disposition of assets sold		(28,938	)		(17,601	)		—
Exploratory well costs charged to exploration expense (a)		(3,256	)		(91,806	)		(17,870	)
Ending capitalized exploratory well costs	$	107,596		$	96,193		$	127,574

(a) Includes an exploratory well credit included in discontinued operations of $117 thousand in 2010, and exploratory well costs included in discontinued operations of $9.9 million in 2009.

Capitalized Exploratory Costs And The Number Of Projects For Which Exploratory Costs Have Been Capitalized

	Year Ended December 31,
	2011		2010		2009
	(in thousands, except well counts)
Capitalized exploratory well costs that have been suspended:
One year or less	$	107,596	$	70,635	$	21,634
More than one year		—		25,558		105,940
	$	107,596	$	96,193	$	127,574
Number of projects with exploratory well costs that have been suspended for a period greater than one year		—		3		8