Selected Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended												12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues		$ 172,292	$ 212,393	$ 214,447	$ 255,099	$ 378,551		$ 400,974		$ 405,431		$ 387,988		$ 854,231	$ 1,572,944	$ 1,351,850
Gross profit (loss)	[1]	(492,636)	(314,409)	(419,666)	(389,451)	(89,796)		103,983		113,973		115,143
Net income (loss)		$ (309,337)	$ (205,281)	$ (274,389)	$ (248,354)	$ (42,551)		$ 67,522		$ 54,360		$ 56,945		$ (1,037,361)	$ 136,276	$ 184,746
Net income (loss) per common share:
Basic		$ (6.29)	$ (4.18)	$ (5.58)	$ (5.07)	$ (0.88)		$ 1.39		$ 1.12		$ 1.17		$ (21.12)	$ 2.80	$ 3.83
Diluted		$ (6.29)	$ (4.18)	$ (5.58)	$ (5.07)	$ (0.88)	[2]	$ 1.37	[2]	$ 1.11	[2]	$ 1.17	[2]	$ (21.12)	$ 2.78	$ 3.80

[1] Gross profit (loss) excludes general and administrative expense, interest expense, (gain) loss on disposition of assets, gain (loss) on non-designated hedges and hedge ineffectiveness, net, income taxes, and other income (loss).

[2] Due to the effect of the loss in the fourth quarter, the diluted earnings per share for the year's four quarters does not equal annual earnings per share.