Condensed Consolidated Balance Sheets (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 1,223	$ 1,359
Accounts receivable, net of allowance for doubtful accounts of $5,083 both at June 30, 2011 and at December 31, 2010	139,116	130,142
Materials and supplies	6,772	6,316
Current derivative assets (Note 10)	5,402	5,568
Current income tax receivable	19,203	25,211
Current deferred tax asset	11,773	13,537
Prepaid expenses and other	6,342	6,047
Total current assets	189,831	188,180
Property and equipment:
Drilling equipment	1,353,142	1,273,861
Oil and natural gas properties on the full cost method:
Proved properties	2,973,505	2,738,093
Undeveloped leasehold not being amortized	184,084	175,065
Gas gathering and processing equipment	236,369	199,564
Transportation equipment	33,508	31,688
Other	32,180	28,511
Property, plant and equipment, gross, total	4,812,788	4,446,782
Less accumulated depreciation, depletion, amortization and impairment	2,172,066	2,047,031
Net property and equipment	2,640,722	2,399,751
Deferred financing costs, net	5,913	0
Goodwill	62,808	62,808
Other intangible assets, net	2,460	3,022
Non-current derivative assets (Note 10)	3,028	2,537
Other assets	12,740	12,942
Total assets	2,917,502	2,669,240
Current liabilities:
Accounts payable	88,637	89,885
Accrued liabilities (Note 5)	35,259	30,093
Contract advances	1,803	2,582
Current portion of derivative liabilities (Note 10)	10,314	14,446
Current portion of other long-term liabilities (Note 6)	10,120	10,122
Total current liabilities	146,133	147,128
Long-term debt (Note 6)	250,000	163,000
Long-term derivative liabilities (Note 10)	1,718	4,359
Other long-term liabilities (Note 6)	92,917	88,030
Deferred income taxes	613,476	556,106
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued	0	0
Common stock, $.20 par value, 175,000,000 shares authorized, 48,159,720 and 47,910,431 shares issued, respectively	9,530	9,493
Capital in excess of par value	401,571	393,501
Accumulated other comprehensive loss	(3,163)	(6,851)
Retained earnings	1,405,320	1,314,474
Total shareholders' equity	1,813,258	1,710,617
Total liabilities and shareholders' equity	$ 2,917,502	$ 2,669,240