Suspended Exploratory Well Costs (Tables)

9 Months Ended

Sep. 30, 2011

Extractive Industries [Abstract]

Suspended Exploratory Well Costs

	September 30,			December 31,
	2011			2010
Beginning balance at January 1	$	23,908		$	19,052
Additions to capitalized exploratory well costs pending the determination of proved reserves		71,779			28,897
Reclassifications based on determination of proved reserves		(12,488	)		(24,041	)
Capitalized exploratory well costs charged to expense		—			—
Balance at end of period		83,199			23,908
Less exploratory well costs that have been capitalized for a period of one year or less		(68,171	)		(13,181	)
Capitalized exploratory well costs that have been capitalized for a period greater than one year	$	15,028		$	10,727
Number of projects that have exploratory well costs that have been capitalized for a period greater than one year		5			4

Aging of capitalized exploratory well costs that have been suspended for more than one year

	Total		2011		2010		2009		2008
Capitalized exploratory well costs that have been capitalized for more than one year	$	15,028	$	494	$	10,127	$	2,884	$	1,523