Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 298		$ 278
Short-term investments	65		65
Accounts receivable	115,952		93,406
Deferred income taxes	13,779		32,342
Derivative instruments	6,117		2,742
Assets held for sale	14,622		0
Prepaid expenses and other	16,801		14,033
Total current assets	167,634		142,866
Oil and natural gas properties (successful efforts basis), buildings and equipment, net	2,531,393		2,655,792
Derivative instruments	7,027		2,054
Other assets	28,898		37,904
TOTAL ASSETS	2,734,952		2,838,616
Current liabilities:
Accounts payable	126,489		106,459
Revenue and royalties payable	49,253		37,812
Accrued liabilities	35,066		36,234
Line of credit	0		5,300
Derivative instruments	20,365		84,846
Total current liabilities	231,173		270,651
Long-term liabilities:
Deferred income taxes	185,450		329,207
Senior secured revolving credit facility	531,500		170,000
8.25% Senior subordinated notes due 2016	200,000		200,000
10.25% Senior notes due 2014, net of unamortized discount of $6,564 and $11,035, respectively	348,692		438,965
6.75% Senior notes due 2020	300,000		300,000
Asset retirement obligations	64,019	[1]	53,443
Derivative instruments	15,505		33,526
Other long-term liabilities	17,884		18,271
Total long-term liabilities	1,663,050		1,543,412
Commitments and contingencies (Note 10)
Shareholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares outstanding	0		0
Capital stock, $0.01 par value:
Capital in excess of par value	350,158		327,369
Accumulated other comprehensive loss	(5,517)		(43,806)
Retained earnings	495,549		740,458
Total shareholders' equity	840,729		1,024,553
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	2,734,952		2,838,616
Class A
Capital stock, $0.01 par value:
Common Stock	521		514
Class B
Capital stock, $0.01 par value:
Common Stock	$ 18		$ 18

[1] The asset retirement obligation related to the Nevada Assets, which were held for sale as of December 31, 2011, was $0.7 million at December 31, 2011 and is included in the asset retirement obligations liability on the December 31, 2011 Balance Sheets. See Note 3 to the Financial Statements.