Consolidated Statement of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues [Abstract]
Natural gas sales	$ 202,200	$ 191,040
Oil sales	23,426	35,103
Oil and Gas Revenue	225,626	226,143
Operating Expenses [Abstract]
Lease operating expenses	18,817	17,002
LGS operating lease expense	5,000	0
Production taxes	16,555	18,219
Gathering fees	11,884	19,552
Transportation charges	20,309	21,056
Depletion, depreciation and amoritzation	61,468	112,702
General and administrative	5,961	5,008
Costs and Expenses	139,994	193,539
Operating Income (Loss)	85,632	32,604
Other Nonoperating Income (Expense) [Abstract]
Interest Expense, Debt	(25,764)	(18,298)
Gain (loss) on commodity derivatives	(44,715)	120,283
Deferred gain on sale of liquids gathering system	2,640	0
Contract Cancellation Fees	0	(4,846)
Other income (expense) net	8	8
Other Nonoperating Income (Expense)	(67,831)	97,147
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest	17,801	129,751
Income Tax Expense (Benefit)	1,368	45,489
Net Income (Loss)	$ 16,433	$ 84,262
Earnings Per Share, Basic [Abstract]
Earnings Per Share, Basic	$ 0.11	$ 0.55
Fully Diluted Earnings per Share:
Earnings Per Share, Diluted	$ 0.11	$ 0.55
Weighted Average Number of Shares Outstanding, Basic	152,947	152,601
Weighted Average Number of Shares Outstanding, Diluted	154,470	153,518