Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 81	$ 298
Restricted short-term investments	65	65
Accounts receivable	106,537	115,952
Deferred income taxes	0	13,779
Derivative instruments	28,650	6,117
Assets held for sale	0	14,622
Prepaid expenses and other	17,631	16,801
Total current assets	152,964	167,634
Oil and natural gas properties (successful efforts basis), buildings and equipment, net	2,810,963	2,531,393
Derivative instruments	20,092	7,027
Other assets	32,035	28,898
TOTAL ASSETS	3,016,054	2,734,952
Current liabilities:
Accounts payable	138,104	126,489
Revenue and royalties payable	36,941	49,253
Accrued liabilities	41,138	35,066
Derivative instruments	2	20,365
Deferred income taxes	9,111	0
Total current liabilities	225,296	231,173
Long-term liabilities:
Deferred income taxes	230,736	185,450
Senior secured revolving credit facility	400,500	531,500
8.25% Senior subordinated notes due 2016	0	200,000
Asset retirement obligation	80,880	64,019
Derivative instruments	0	15,505
Other long-term liabilities	17,662	17,884
Total long-term liabilities	1,831,952	1,663,050
Shareholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares outstanding	0	0
Capital in excess of par value	359,813	350,158
Accumulated other comprehensive loss	(3,241)	(5,517)
Retained earnings	601,692	495,549
Total shareholders' equity	958,806	840,729
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	3,016,054	2,734,952
Class A
Capital stock, $0.01 par value:
Common Stock	524	521
Class B
Capital stock, $0.01 par value:
Common Stock	18	18
10.25% Senior notes due 2014, net of unamortized discount
Long-term liabilities:
Senior notes	202,174	348,692
6.75% Senior notes due 2020
Long-term liabilities:
Senior notes	300,000	300,000
6.375% Senior notes due 2022
Long-term liabilities:
Senior notes	$ 600,000	$ 0