Supplementary Oil and Natural Gas Disclosures (Tables)

12 Months Ended

Dec. 31, 2012

Supplementary Oil and Natural Gas Disclosures (Unaudited) [Abstract]

Schedule of Estimated Net Proved Reserves, Changes in Estimated Net Proved Reserves and Proved Developed Reserves

	Crude Oil (Mbbls)		Gas (Mmcf)		Oil Equivalent (Mboe)
Estimated Proved Reserves:
December 31, 2009		19,923		67,378		31,153
Extensions, discoveries and other additions		652		489		733
Revisions (a)		(1,016)		8,892		466
Production		(2,336)		(15,508)		(4,921)
December 31, 2010		17,223		61,251		27,431
Acquisitions (b)		7,987		8,640		9,427
Extensions, discoveries and other additions		2,266		4,664		3,043
Revisions		2,778		(6,678)		1,666
Production		(2,953)		(9,092)		(4,468)
December 31, 2011		27,301		58,785		37,099
Acquisitions (c)		16,430		115,876		35,742
Extensions, discoveries and other additions		6,388		10,241		8,095
Revisions		1,128		4,033		1,800
Production		(3,805)		(8,996)		(5,304)
December 31, 2012		47,442		179,939		77,432
Proved developed reserves:
December 31, 2010		15,974		56,410		25,376
December 31, 2011		24,791		52,739		33,581
December 31, 2012		37,908		120,687		58,022

Capitalized Costs for Oil and Natural Gas Producing Activities

	Year Ended December 31,
	2012		2011
	(In thousands)
Proved properties	$	1,982,657	$	1,049,140
Unproved properties		36,992		29,382
Accumulated depreciation, depletion and amortization		(424,520)		(303,566)
Net capitalized costs	$	1,595,129	$	774,956

Cost Incurred Associated with Finding, Acquiring and Developing Proved Oil and Natural Gas Reserves

	Year Ended December 31,
	2012		2011		2010
	(In thousands)
Acquisitions — Proved (1)	$	706,322	$	261,812	$	-
Acquisitions — Unproved		7,496		14		623
Exploration		43,338		17,129		31,463
Development (2)		180,938		83,577		25,643
Costs incurred	$	938,094	$	362,532	$	57,729

Standardized Measure of Discounted Future Cash Flows Relating to Proved Oil and Natural Gas Reserves Disclosure

	Year Ended December 31,
	2012		2011
	(In thousands)
Future cash inflows	$	5,401,290	$	3,133,430
Future production costs		(1,823,303)		(1,141,297)
Future development costs (1)		(936,580)		(437,074)
Future income taxes		(537,546)		(322,454)
Future net cash flows after income taxes		2,103,861		1,232,605
10% annual discount for estimated timing of cash flows		(529,579)		(356,436)
Standardized measure of discounted future net cash flows	$	1,574,282	$	876,169

Schedule of Changes in Standardized Measure of Discounted Future Net Cash Flows Applicable to Proved Oil and Natural Gas Reserves

	Year Ended December 31,
	2012		2011
	(In thousands)
Beginning of the period	$	876,169	$	359,458
Sales and transfers of oil and natural gas produced, net of production costs		(317,059)		(266,120)
Net changes in prices and production costs		(244,824)		461,719
Purchase of minerals in place		797,085		230,471
Extensions, discoveries and improved recoveries, net of future production costs		452,258		139,757
Revision of quantity estimates		55,133		54,329
Previously estimated development costs incurred during the period		39,321		27,066
Changes in estimated future development costs		746		24,662
Changes in production rates (timing) and other		(14,157)		(25,655)
Accretion of discount		110,070		41,307
Net change in income taxes		(180,460)		(170,825)
Net increase (decrease)		698,113		516,711
End of period	$	1,574,282	$	876,169

Oil and Natural Gas Computed Price Used in Computation of Discounted Future Net Cash Flows

	2012		2011
per barrel of oil	$	105.13	$	108.48
per Mcf for natural gas	$	2.92	$	4.16