Condensed Balance Sheets (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 248	$ 278
Restricted short-term investments	65	65
Accounts receivable	111,023	93,406
Deferred income taxes	34,252	32,342
Derivative instruments	3,129	2,742
Prepaid expenses and other	15,847	14,033
Total current assets	164,564	142,866
Oil and gas properties (successful efforts basis), buildings and equipment, net	2,959,386	2,655,792
Derivative instruments	1,418	2,054
Other assets	34,939	37,904
TOTAL ASSETS	3,160,307	2,838,616
Current liabilities:
Accounts payable	105,175	106,459
Revenue and royalties payable	33,492	37,812
Accrued liabilities	29,606	36,234
Line of credit	12,700	5,300
Derivative instruments	60,432	84,846
Total current liabilities	241,405	270,651
Long-term liabilities:
Deferred income taxes	362,939	329,207
Senior secured revolving credit facility	395,000	170,000
8.25% Senior subordinated notes due 2016	200,000	200,000
10.25% Senior notes due 2014, net of unamortized discount of $9,702 and $11,035, respectively	440,298	438,965
6.75% Senior notes due 2020	300,000	300,000
Asset retirement obligation	56,885	53,443
Derivative instruments	46,470	33,526
Other long-term liabilities	18,136	18,271
Total long-term liabilities	1,819,728	1,543,412
Shareholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares outstanding
Capital stock, $0.01 par value:
Capital in excess of par value	338,397	327,369
Accumulated other comprehensive loss	(24,761)	(43,806)
Retained earnings	785,003	740,458
Total shareholders' equity	1,099,174	1,024,553
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	3,160,307	2,838,616
Class A
Capital stock, $0.01 par value:
Common Stock	517	514
Class B
Capital stock, $0.01 par value:
Common Stock	$ 18	$ 18