Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 316,918	$ 537,484
Accounts receivable:
Trade, net of allowance for doubtful accounts of $689 and $806 as of March 31, 2012 and December 31, 2011, respectively	297,700	275,991
Due from affiliates	1,354	7,822
Income taxes receivable	3	3
Inventories	281,890	241,609
Prepaid expenses	13,152	14,263
Deferred income taxes	87,362	77,005
Discontinued operations held for sale	78,643	73,349
Other current assets:
Derivatives	279,919	238,835
Other	10,168	12,936
Total current assets	1,367,109	1,479,297
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	12,722,856	12,013,805
Unproved properties	252,435	235,527
Accumulated depletion, depreciation and amortization	(3,821,083)	(3,648,465)
Total property, plant and equipment	9,154,208	8,600,867
Goodwill	298,142	298,142
Other property and equipment, net	613,834	573,075
Other assets:
Investment in unconsolidated affiliate	176,513	169,532
Derivatives	264,362	243,240
Other, net of allowance for doubtful accounts of $332 and $340 as of March 31, 2012 and December 31, 2011, respectively	151,391	160,008
Assets, Total	12,025,559	11,524,161
Accounts payable:
Trade	790,679	647,455
Due to affiliates	26,798	68,756
Interest payable	35,323	57,240
Income taxes payable	22,017	9,788
Discontinued operations held for sale	84,146	75,901
Other current liabilities:
Derivatives	83,952	74,415
Deferred revenue	31,610	42,069
Other	35,597	36,174
Total current liabilities	1,110,122	1,011,798
Long-term debt	2,620,615	2,528,905
Derivatives	58,176	33,561
Deferred income taxes	2,181,381	2,077,164
Other liabilities	222,594	221,595
Stockholders' equity:
Common stock, $.01 par value; 500,000,000 shares authorized; 134,751,627 and 133,121,092 shares issued at March 31, 2012 and December 31, 2011, respectively	1,348	1,331
Additional paid-in capital	3,640,595	3,613,808
Treasury stock, at cost: 11,727,409 and 11,264,936 at March 31, 2012 and December 31, 2011, respectively	(511,630)	(458,281)
Retained earnings	2,543,873	2,335,066
Accumulated other comprehensive loss - net deferred hedge losses, net of tax	(1,550)	(3,130)
Total equity attributable to common stockholders	5,672,636	5,488,794
Noncontrolling interests in consolidating subsidiaries	160,035	162,344
Total equity	5,832,671	5,651,138
Liabilities and Stockholders' Equity, Total	$ 12,025,559	$ 11,524,161