Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 104	$ 298
Restricted short-term investments	125	65
Accounts receivable	114,916	115,952
Deferred income taxes	0	13,779
Derivative instruments	10,573	6,117
Assets held for sale	0	14,622
Prepaid expenses and other	15,503	16,801
Total current assets	141,221	167,634
Oil and natural gas properties (successful efforts basis), buildings and equipment, net	3,010,126	2,531,393
Derivative instruments	11,122	7,027
Other assets	30,891	28,898
TOTAL ASSETS	3,193,360	2,734,952
Current liabilities:
Accounts payable	155,766	126,489
Revenue and royalties payable	44,405	49,253
Accrued liabilities	48,392	35,066
Derivative instruments	1,309	20,365
Deferred income taxes	3,486	0
Total current liabilities	253,358	231,173
Long-term liabilities:
Deferred income taxes	248,018	185,450
Senior secured revolving credit facility	510,000	531,500
8.25% Senior subordinated notes due 2016	0	200,000
Asset retirement obligation	84,257	64,019
Derivative instruments	1,358	15,505
Other long-term liabilities	17,541	17,884
Total long-term liabilities	1,963,716	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	362,051	350,158
Accumulated other comprehensive loss	(1,736)	(5,517)
Retained earnings	615,429	495,549
Total shareholders' equity	976,286	840,729
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	3,193,360	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	202,542	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