CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Net income (loss)	$ 19,178		$ (53,836)		$ 87,551		$ (39,960)
Other comprehensive income:
Realized loss (gain) on hedge derivative contract settlements reclassified into natural gas, NGLs and oil sales from other comprehensive income, net of taxes			(37,495)	[1]	(14,840)	[1]	(120,871)	[1]
De-designated hedges reclassified into natural gas, NGLs and oil sales, net of taxes	(16,717)	[2]			(42,758)	[2]
De-designated hedges reclassified to derivative fair value income, net of taxes	(438)	[3]			(2,376)	[3]
Change in unrealized deferred hedging (losses) gains, net of taxes			(52,246)	[4]	(4,203)	[4]	31,541	[4]
Total comprehensive income (loss)	$ 2,023		$ (143,577)		$ 23,374		$ (129,290)

[1] Amounts are net of income tax expense of $23,972 for the three months ended September 30, 2012 and $9,488 and $76,806 for the nine months ended September 30, 2013 and 2012.

[2] Amounts are net of income tax expense of $10,688 for the three months ended September 30, 2013 and $27,337 for the nine months ended September 30, 2013.

[3] Amounts relate to transactions not probable of occurring and are presented net of income tax expense of $279 for the three months ended September 30, 2013 and $1,518 for the nine months ended September 30, 2013.

[4] Amounts are net of income tax expense of $33,403 for the three months ended September 30, 2012 and income tax benefit of $21,780 for the nine months ended September 30, 2012. Amounts are net of income tax expense of $2,687 for the nine months ended September 30, 2013.