Acquisitions and Divestitures (Tables)

9 Months Ended

Sep. 30, 2012

Business Combinations [Abstract]

Schedule of Purchase Price Allocation

The following table summarizes the preliminary purchase price and the preliminary estimated values of assets acquired and liabilities assumed. It is based on information available to us at the time these unaudited condensed consolidated financial statements were prepared. We believe these estimates are reasonable; however, the estimates are subject to change as additional information becomes available and is assessed by us (in thousands):

Preliminary Purchase Price
Total consideration given	$	594,463
Preliminary Allocation of Purchase Price
Oil and natural gas properties included in the full cost pool:
Proved oil and natural gas properties	$	260,798
Undeveloped oil and natural gas properties	355,180
Total oil and natural gas properties included in the full cost pool (1)	615,978
Equipment and facilities	25,163
Asset retirement obligation	(46,678		)
Fair value of net assets acquired	$	594,463

(1) We used a discounted cash flow model and made market assumptions as to future commodity prices, projections of estimated quantities of oil and natural gas reserves, expectations for timing and amount of future development and operating costs, projections of future rates of production, expected recovery rates and risk adjusted discount rates.

Pro Forma Results

Future results may vary significantly from the results reflected in this pro forma financial information because of future events and transactions, as well as other factors.

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
	(In thousands, except per share data)
Pro forma:
Revenues	$	335,394	$	354,320	$	1,041,350	$	964,165
Net income	$	47,186	$	60,897	$	140,670	$	171,445
Net income per common share:
Basic	$	0.98	$	1.28	$	2.94	$	3.60
Diluted	$	0.98	$	1.27	$	2.92	$	3.58