Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 317,769	$ 537,484
Accounts receivable:
Trade, net of allowance for doubtful accounts of $706 and $806 as of June 30, 2012 and December 31, 2011, respectively	250,192	275,991
Due from affiliates	2,301	7,822
Income taxes receivable	2,417	3
Inventories	277,539	241,609
Prepaid expenses	28,213	14,263
Discontinued operations held for sale	70,177	73,349
Other current assets:
Derivatives	308,762	238,835
Other	26,663	12,936
Total current assets	1,284,033	1,402,292
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	12,964,291	12,013,805
Unproved properties	296,827	235,527
Accumulated depletion, depreciation and amortization	(4,013,770)	(3,648,465)
Total property, plant and equipment	9,247,348	8,600,867
Goodwill	298,142	298,142
Other property and equipment, net	1,134,532	573,075
Other assets:
Investment in unconsolidated affiliate	184,374	169,532
Derivatives	260,929	243,240
Other, net of allowance for doubtful accounts of $655 and $340 as of June 30, 2012 and December 31, 2011, respectively	160,376	160,008
Assets, Total	12,569,734	11,447,156
Accounts payable:
Trade	769,611	647,455
Due to affiliates	39,547	68,756
Interest payable	57,329	57,240
Income taxes payable	1,881	9,788
Deferred Tax Liabilities, Net, Current	89,656	57,713
Discontinued operations held for sale	77,310	75,901
Other current liabilities:
Derivatives	30,650	74,415
Deferred revenue	21,150	42,069
Other	41,857	36,174
Total current liabilities	1,128,991	1,069,511
Long-term debt	3,285,497	2,528,905
Derivatives	17,785	33,561
Deferred income taxes	2,154,301	1,942,446
Other liabilities	226,184	221,595
Stockholders' equity:
Common stock, $.01 par value; 500,000,000 shares authorized; 134,763,095 and 133,121,092 shares issued at June 30, 2012 and December 31, 2011, respectively	1,348	1,331
Additional paid-in capital	3,611,799	3,613,808
Treasury stock at cost: 11,727,359 and 11,264,936 at June 30, 2012 and December 31, 2011, respectively	(511,628)	(458,281)
Retained earnings	2,473,504	2,335,066
Accumulated other comprehensive loss - net deferred hedge losses, net of tax	0	(3,130)
Total equity attributable to common stockholders	5,575,023	5,488,794
Noncontrolling interests in consolidating subsidiaries	181,953	162,344
Total equity	5,756,976	5,651,138
Commitments and contingencies
Liabilities and Stockholders' Equity, Total	$ 12,569,734	$ 11,447,156