CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income		$ (713,685)	$ 634,382	$ 115,722
Other comprehensive income:
Realized gain on hedge derivative contract settlements reclassified into natural gas, NGLs and oil sales from other comprehensive income, net of taxes	[1]	0	0	(14,840)
De-designated hedges reclassified into natural gas, NGLs and oil sales, net of taxes	[2]	0	(6,236)	(56,254)
De-designated hedges reclassified to derivative fair value, net of taxes	[3]	0	0	(2,376)
Change in unrealized deferred hedging losses, net of taxes	[4]	0	0	(4,203)
Total comprehensive (loss) income	[5]	$ (713,685)	$ 628,146	$ 38,049

[1] Amounts are net of income tax benefit of $9,488 for the year ended December 31, 2013.

[2] Amounts are net of income tax benefit of $3,986 for the year ended December 31, 2014 compared to $35,968 for the year ended December 31, 2013.

[3] Amounts relate to transactions not probable of occurring and are presented net of income tax benefit of $1,517 for the year ended December 31, 2013.

[4] Amounts are net of income tax benefit of $2,687 for the year ended December 31, 2013.

[5] As of March 31, 2013, we elected to discontinue hedge accounting prospectively, and as of December 31, 2014, all remaining accumulated other comprehensive income had been transferred to earnings.