Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 537,484	$ 111,160
Accounts receivable:
Trade, net of allowance for doubtful accounts of $806 and $1,155 as of December 31, 2011 and 2010, respectively	275,991	237,511
Due from affiliates	7,822	7,792
Income taxes receivable	3	30,901
Inventories	241,609	173,615
Prepaid expenses	14,263	11,441
Deferred income taxes	77,005	156,650
Discontinued operations held for sale	73,349	281,741
Other current assets:
Derivatives	238,835	171,679
Other	12,936	14,693
Total current assets	1,479,297	1,197,183
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	12,013,805	10,739,114
Unproved properties	235,527	191,112
Accumulated depletion, depreciation and amortization	(3,648,465)	(3,366,440)
Total property, plant and equipment	8,600,867	7,563,786
Goodwill	298,142	298,182
Other property and equipment, net	573,075	283,542
Other assets:
Investment in unconsolidated affiliate	169,532	72,045
Derivatives	243,240	151,011
Other, net of allowance for doubtful accounts of $340 and $2,519 as of December 31, 2011 and 2010, respectively	160,008	113,353
Assets, Total	11,524,161	9,679,102
Accounts payable:
Trade	647,455	354,890
Due to affiliates	68,756	64,260
Interest payable	57,240	59,008
Income taxes payable	9,788	19,168
Deferred income taxes		1,144
Discontinued operations held for sale	75,901	108,592
Other current liabilities:
Derivatives	74,415	80,997
Deferred revenue	42,069	44,951
Other	36,174	36,210
Total current liabilities	1,011,798	769,220
Long-term debt	2,528,905	2,601,670
Derivatives	33,561	56,574
Deferred income taxes	2,077,164	1,751,310
Deferred revenue		42,069
Other liabilities	221,595	232,234
Stockholders' equity:
Common stock, $.01 par value; 500,000,000 shares authorized; 133,121,092 and 126,212,256 shares issued at December 31, 2011 and 2010, respectively	1,331	1,262
Additional paid-in capital	3,613,808	3,022,768
Treasury stock, at cost: 11,264,936 and 10,903,743 shares at December 31, 2011 and 2010, respectively	(458,281)	(421,235)
Retained earnings	2,335,066	1,510,427
Accumulated other comprehensive income (loss) - net deferred hedge gains (losses), net of tax	(3,130)	7,361
Total stockholders' equity attributable to common stockholders	5,488,794	4,120,583
Noncontrolling interest in consolidating subsidiaries	162,344	105,442
Total stockholders' equity	5,651,138	4,226,025
Commitments and contingencies
Liabilities and Stockholders' Equity, Total	$ 11,524,161	$ 9,679,102