Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Inventory

Inventory consists of the following:

	December 31,
	2012		2011
	(In thousands)
Equipment and materials	$	16,438	$	2,709
Crude oil inventory		4,269		834
	$	20,707	$	3,543

Net Changes in Capitalized Exploratory Well Costs

Net changes in capitalized exploratory well costs are reflected in the following table for the periods presented:

	December 31,
	2012			2011			2010
	(In thousands)
Beginning of period	$	20,207		$	5,176		$	427
Exploratory well cost additions (pending determination of proved reserves)		160,813			73,947			39,708
Exploratory well cost reclassifications (successful determination of proved reserves)		(140,091	)		(57,646	)		(34,959	)
Exploratory well dry hole costs (unsuccessful in adding proved reserves)		(505	)		(1,270	)		—
End of period	$	40,424		$	20,207		$	5,176