Consolidated Statements Of Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings (Defecit) [Member]	Total [Member]
Balances at Dec. 31, 2010		$ 1,755	$ 714,869	$ (41,487)	$ 130,187	$ 264,581	$ 1,069,905
Net income (loss)	90,046					90,046	90,046
Hedge settlements reclassified into earnings from AOCI, net of income tax					58,125		58,125
Net change in derivative fair value, net of income tax	156,160				156,160		156,160
Foreign currency translation adjustment	(13,364)				(13,364)		(13,364)
Issuance & vesting of stock compensation		(13)	(20,849)	(4,864)			(15,998)
Stock option exercises		2	1,297				1,299
Balances at Dec. 31, 2011		1,770	737,015	(46,351)	214,858	354,627	1,261,919
Net income (loss)	(2,352,606)					(2,352,606)	(2,352,606)
Hedge settlements reclassified into earnings from AOCI, net of income tax					128,161		128,161
Net change in derivative fair value, net of income tax	74,384				74,384		74,384
Foreign currency translation adjustment	412				412		412
Issuance & vesting of stock compensation		(19)	(14,369)	(3,144)			(11,244)
Stock option exercises		1	10				11
Balances at Dec. 31, 2012		1,790	751,394	(49,495)	161,493	(1,997,979)	(1,132,797)
Net income (loss)	161,618					161,618	161,618
Hedge settlements reclassified into earnings from AOCI, net of income tax					46,931		46,931
Net change in derivative fair value, net of income tax	0
Foreign currency translation adjustment	(4,681)				(4,681)		(4,681)
Issuance & vesting of stock compensation		(50)	(18,698)	(1,927)			(16,821)
Balances at Dec. 31, 2013		$ 1,840	$ 770,092	$ (51,422)	$ 109,881	$ (1,836,361)	$ (1,005,970)