Condensed Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
REVENUES
Sales of oil and natural gas	$ 233,653	$ 187,389
Sales of electricity	5,980	6,412
Natural gas marketing	1,859	3,685
Gain on sale of assets	1,763	0
Interest and other income, net	747	128
TOTAL REVENUES	244,002	197,614
EXPENSES
Operating costs—oil and natural gas production	54,252	57,083
Operating costs- electricity generation	5,017	6,113
Production taxes	10,658	7,391
Depreciation, depletion & amortization- oil and natural gas production	47,956	52,109
Depreciation, depletion & amortization- electricity generation	466	501
Natural gas marketing	1,777	3,516
General and administrative	17,741	16,291
Interest	20,104	15,655
Dry hole abandonment impairment and exploration	3,036	113
Gain on purchase	0	(1,046)
Realized and unrealized loss on derivatives, net	28,481	127,516
TOTAL EXPENSES	189,488	285,242
Earnings (loss) before income taxes	54,514	(87,628)
Income tax provision (benefit)	20,616	(35,131)
Net earnings (loss)	$ 33,898	$ (52,497)
Basic net earnings (loss) per share (in dollars per share)	$ 0.62	$ (0.98)
Diluted net earnings (loss) per share (in dollars per share)	$ 0.61	$ (0.98)
Dividends per share (in dollars per share)	$ 0.080	$ 0.075