CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 208,938		$ 70,690		$ 334,325		$ 163,939
Reclassification to earnings	0	[1]	308	[1]	0	[1]	1,115	[1]
Pension liability adjustment	196		0		526		(3)
Total other comprehensive income, net of tax	196		308		526		1,112
Total comprehensive income	$ 209,134		$ 70,998		$ 334,851		$ 165,051

[1] Reclassification from accumulated other comprehensive loss (“AOCL”) related to de-designated hedges. As of December 31, 2013, all commodity derivative contracts that had been designated as cash flow hedges were settled and reclassified into earnings from AOCL.