Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 1,023	$ 835
Accounts receivable, net of allowance for doubtful accounts of $5,343 both at September 30, 2012 and at December 31, 2011	160,666	165,276
Materials and supplies	10,151	8,202
Current derivative asset (Note 10)	14,517	31,938
Current deferred tax asset	10,936	10,936
Prepaid expenses and other	12,791	11,278
Total current assets	210,084	228,465
Property and equipment:
Drilling equipment	1,469,511	1,423,570
Oil and natural gas properties on the full cost method:
Proved properties	3,641,786	3,302,032
Undeveloped leasehold not being amortized	578,803	185,632
Gas gathering and processing equipment	398,810	278,919
Transportation equipment	37,487	34,118
Other	53,278	37,544
Property, plant and equipment, gross, total	6,179,675	5,261,815
Less accumulated depreciation, depletion, amortization and impairment	2,660,250	2,319,484
Net property and equipment	3,519,425	2,942,331
Debt issuance cost	13,767	5,671
Goodwill	62,808	62,808
Other intangible assets, net	934	1,855
Non-current derivative asset (Note 10)	1,948	4,514
Other assets	12,117	11,076
Total assets	3,821,083	3,256,720
Current liabilities:
Accounts payable	145,362	143,311
Accrued liabilities (Note 5)	82,709	51,733
Income taxes payable	2,002	781
Contract advances	5,110	2,055
Current portion of derivative liabilities (Note 10)	851	2,657
Current portion of other long-term liabilities (Note 6)	11,413	12,213
Total current liabilities	247,447	212,750
Long-term debt (Note 6)	645,154	300,000
Non-current derivative liabilities (Note 10)	1,214	0
Other long-term liabilities (Note 6)	164,170	113,830
Deferred income taxes	734,122	683,123
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, 48,565,428 and 48,151,442 shares issued, respectively	9,591	9,541
Capital in excess of par value	419,409	408,109
Accumulated other comprehensive income	9,912	19,026
Retained earnings	1,590,064	1,510,341
Total shareholders' equity	2,028,976	1,947,017
Total liabilities and shareholders' equity	$ 3,821,083	$ 3,256,720