CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 184	$ 119,194
Accounts receivable	235,887	210,368
Refundable income taxes	3,242	5,581
Prepaid expenses and other	39,014	68,026
Derivative asset	41,865	55,813
Deferred income taxes	5,746	4,222
Total current assets	325,938	463,204
Property and equipment (successful efforts method), at cost:
Land	1,845	1,548
Proved Oil and Gas Property, Successful Effort Method	5,197,761	4,378,987
Less - accumulated depletion, depreciation, and amortization	(2,190,507)	(1,766,445)
Unproved Oil and Gas Property, Successful Effort Method	160,468	120,966
Wells in progress	264,634	273,428
Materials inventory, at lower of cost or market	12,718	16,537
Assets Held-for-sale, at Carrying Value	19,503	246
Other property and equipment, net of accumulated depreciation	135,376	71,369
Total property and equipment, net	3,601,798	3,096,636
Other noncurrent assets:
Derivative asset	22,383	31,062
Restricted Cash and Cash Equivalents, Noncurrent	93,771	124,703
Other Assets, Noncurrent	80,062	83,375
Total other noncurrent assets	196,216	239,140
Total Assets	4,123,952	3,798,980
Current liabilities:
Accounts payable and accrued expenses	474,573	456,999
Derivative liability	19,352	42,806
Deposit associated with oil and gas properties held for sale	6,000	6,000
Total current liabilities	499,925	505,805
Noncurrent liabilities:
Long-term credit facility	228,000	0
3.50% Senior Convertible Notes, net of unamortized discount	0	285,069
6.625% Senior Notes due 2019	350,000	350,000
6.50% Senior Notes due 2021	350,000	350,000
6.50% Senior Notes due 2023	400,000	0
Asset retirement obligation	90,788	87,167
Asset retirement obligation associated with oil and gas properties held for sale (note 3)	749	1,277
Net Profits Plan liability	90,389	107,731
Deferred income taxes	573,577	568,263
Derivative liability	8,802	12,875
Other Liabilities, Noncurrent	57,680	67,853
Total noncurrent liabilities	2,149,985	1,830,235
Commitments and contingencies (note 7)
Stockholders' equity:
Common stock, outstanding, net of treasury shares	661	641
Additional paid-in capital	222,812	216,966
Treasury stock at cost	(1,221)	(1,544)
Retained earnings	1,257,534	1,251,157
Accumulated other comprehensive loss	(5,744)	(4,280)
Total stockholders' equity	1,474,042	1,462,940
Total Liabilities and Stockholders' Equity	$ 4,123,952	$ 3,798,980