CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Net income	$ 143,983		$ 55,676		$ 68,373		$ 13,876
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		[1]	(47,934)	[1]	(14,840)	[1]	(83,376)	[1]
Amortization related to de-designated hedges reclassified into natural gas, NGLs and oil sales, net of taxes	(18,616)	[2]		[2]	(26,041)	[2]		[2]
De-designated hedges reclassified to derivative fair value income, net of taxes	(547)	[3]		[3]	(1,937)	[3]		[3]
Change in unrealized deferred hedging (losses) gains, net of taxes			4,813	[4]	(4,203)	[4]	83,787	[4]
Total comprehensive income	$ 124,820		$ 12,555		$ 21,352		$ 14,287

[1] Presented net of income tax expense of $30,647 for the three months ended June 30, 2012 and $9,488 and $52,834 for the six months ended June 30, 2013 and 2012.

[2] Presented net of income tax expense of $11,902 for the three months ended June 30, 2013 and $16,649 for the six months ended June 30, 2013.

[3] Amounts relate to transactions not probable of occurring and are presented net of income tax expense of $350 for the three months ended June 30, 2013 and $1,239 for the six months ended June 30, 2013.

[4] Presented net of income tax benefit of $3,077 for the three months ended June 30, 2012 and $55,184 for the six months ended June 30, 2012. Presented net of income tax expense of $2,687 for the six months ended June 30, 2013.