Supplemental Oil And Gas Disclosures (Tables)

12 Months Ended

Dec. 31, 2011

Supplemental Oil And Gas Disclosures [Abstract]

Schedule Of Capitalized Costs And Costs Incurred On Oil And Gas Properties

	2011			2010			2009
	(In thousands)
Capitalized costs:
Proved properties	$	3,302,032		$	2,738,093		$	2,309,193
Unproved properties		185,632			175,065			140,129
		3,487,664			2,913,158			2,449,322
Accumulated depreciation, depletion, amortization and impairment		(1,724,312	)		(1,542,352	)		(1,424,559	)
Net capitalized costs	$	1,763,352		$	1,370,806		$	1,024,763
Cost incurred:
Unproved properties acquired	$	70,999		$	75,739		$	37,137
Proved properties acquired		50,013			50,000			3,722
Exploration		43,836			48,304			30,547
Development		391,862			279,903			154,579
Asset retirement obligation		23,345			9,924			4,565
Total costs incurred	$	580,055		$	463,870		$	230,550

Schedule Of The Oil And Natural Gas Property Costs Not Being Amortized

	2011		2010		2009		2008 and Prior		Total
	(In thousands)
Undeveloped Leasehold Acquired	$	59,691	$	49,923	$	17,766	$	58,252	$	185,632

Results Of Operations For Producing Activities

	2011			2010			2009
	(In thousands)
Revenues	$	504,739		$	392,229		$	352,572
Production costs		(115,400	)		(91,143	)		(75,214	)
Depreciation, depletion, amortization and impairment		(181,960	)		(117,793	)		(394,942	)
		207,379			183,293			(117,584	)
Income tax (expense) benefit		(80,048	)		(70,110	)		43,153
Results of operations for producing activities (excluding corporate overhead and financing costs)	$	127,331		$	113,183		$	(74,431	)

Schedule Of Proved Developed And Undeveloped Oil And Gas Reserve Quantities

	Oil Bbls			Liquids Bbls			Natural Gas Mcf
	(In thousands)
2011:
Proved developed and undeveloped reserves:
Beginning of year		17,494			16,117			420,486
Revision of previous estimates (1)		374			2,112			(30,510	)
Extensions and discoveries		3,477			3,924			39,836
Infill reserves in existing proved fields		1,229			1,780			15,592
Purchases of minerals in place		192			393			40,835
Production		(2,511	)		(2,239	)		(44,104	)
Sales		0			0			0
End of Year		20,255			22,087			442,135
Proved developed reserves:
Beginning of year		12,773			12,088			346,928
End of year		15,618			16,649			372,311
Proved undeveloped reserves:
Beginning of year		4,721			4,029			73,558
End of year		4,637			5,438			69,824
2010:
Proved developed and undeveloped reserves:
Beginning of year		11,669			14,653			419,061
Revision of previous estimates (1)		434			(1,559	)		(25,007	)
Extensions and discoveries		3,473			878			31,328
Infill reserves in existing proved fields		2,152			3,482			34,128
Purchases of minerals in place		1,293			212			1,732
Production		(1,521	)		(1,549	)		(40,756	)
Sales		(6	)		0			0
End of Year		17,494			16,117			420,486
Proved developed reserves:
Beginning of year		9,183			11,538			338,217
End of year		12,773			12,088			346,928
Proved undeveloped reserves:
Beginning of year		2,486			3,115			80,844
End of year		4,721			4,029			73,558
2009:
Proved developed and undeveloped reserves:
Beginning of year		9,699			10,171			450,135
Revision of previous estimates (1)		459			2,793			(57,393	)
Extensions and discoveries		2,135			1,996			50,480
Infill reserves in existing proved fields (2)		618			1,174			19,872
Purchases of minerals in place		44			7			30
Production		(1,286	)		(1,488	)		(44,063	)
End of Year		11,669			14,653			419,061
Proved developed reserves:
Beginning of year		7,508			8,638			355,824
End of year		9,183			11,538			338,217
Proved undeveloped reserves:
Beginning of year		2,191			1,533			94,311
End of year		2,486			3,115			80,844

(1) Natural gas revisions of previous estimates decreased primarily due to a decline in natural gas prices.

(2) Previously included in 'Extensions, discoveries and other additions'.

Standardized Measure Of Discounted Future Cash Flows Relating To Proved Reserves Disclosure

	2011			2010			2009
	(In thousands)
Future cash flows	$	4,583,629		$	3,745,046		$	2,403,892
Future production costs		(1,277,856	)		(1,054,630	)		(777,725	)
Future development costs		(340,992	)		(303,152	)		(195,486	)
Future income tax expenses		(952,736	)		(799,260	)		(433,366	)
Future net cash flows		2,012,045			1,588,004			997,315
10% annual discount for estimated timing of cash flows		(924,136	)		(732,918	)		(450,980	)
Standardized measure of discounted future net cash flows relating to proved oil, NGLs and natural gas reserves	$	1,087,909		$	855,086		$	546,335

Schedule Of Principal Sources Of Changes In Standardized Measure Of Discounted Future Net Cash Flows

	2011			2010			2009
	(In thousands)
Sales and transfers of oil and natural gas produced, net of production costs	$	(389,339	)	$	(301,086	)	$	(277,358	)
Net changes in prices and production costs		115,852			379,097			(145,839	)
Revisions in quantity estimates and changes in production timing		(38,336	)		(67,116	)		(54,327	)
Extensions, discoveries and improved recovery, less related costs		401,134			340,771			136,695
Changes in estimated future development costs		37,742			15,974			100,304
Previously estimated cost incurred during the period		45,327			45,327			16,301
Purchases of minerals in place		58,567			42,280			1,288
Sales of minerals in place		(29	)		(120	)		0
Accretion of discount		128,492			77,536			89,256
Net change in income taxes		(60,675	)		(200,815	)		39,062
Other—net		(65,912	)		(23,097	)		16,479
Net change		232,823			308,751			(78,139	)
Beginning of year		855,086			546,335			624,474
End of year	$	1,087,909		$	855,086		$	546,335