Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Sales of products	$ 120,543	$ 115,847	$ 374,767	$ 284,353
Cost of sales and other direct production costs	41,639	46,357	125,033	118,172
Depreciation, depletion and amortization	11,099	14,966	34,565	46,055
[CostOfRevenue]	52,738	61,323	159,598	164,227
Gross profit	67,805	54,524	215,169	120,126
Other operating expenses:
General and administrative	5,559	3,684	14,808	12,461
Exploration	9,872	6,917	19,012	16,166
Pre-development	1,752		1,752
Other operating expense	1,612	1,460	5,699	4,025
Provision for closed operations and environmental matters	5,521	962	7,883	5,727
[OperatingExpenses]	24,316	13,023	49,154	38,379
Income from operations	43,489	41,501	166,015	81,747
Other income (expense):
Gain (loss) on sale or impairment of investments			611	(151)
Gain (loss) on derivative contracts	40,382	(13,195)	38,907	(11,196)
Interest and other income (expense)	(214)	70	(91)	137
Interest expense	(411)	(505)	(2,384)	(1,712)
[NonoperatingIncomeExpense]	39,757	(13,630)	37,043	(12,922)
Income before income taxes	83,246	27,871	203,058	68,825
Income tax provision	(27,325)	(8,080)	(70,463)	(10,106)
Net income	55,921	19,791	132,595	58,719
Reclassification of net (gain) loss on sale or impairment of marketable securities included in net income			(611)	739
Unrealized holding gains (losses) on investments	(798)	183	(913)	(1,305)
Comprehensive income	55,123	19,974	131,071	58,153
Basic income per common share after preferred dividends (in Dollars per share)	$ 0.20	$ 0.06	$ 0.47	$ 0.19
Diluted income per common share after preferred dividends (in Dollars per share)	$ 0.19	$ 0.06	$ 0.45	$ 0.18
Weighted average number of common shares outstanding - basic (in Shares)	279,541	256,095	279,067	249,039
Weighted average number of common shares outstanding - diluted (in Shares)	295,000	270,508	295,739	266,145
Preferred stock dividends	(138)	(3,408)	(414)	(10,225)
Income applicable to common shareholders	$ 55,783	$ 16,383	$ 132,181	$ 48,494