Derivatives (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Amount of Gain or (Loss) Recognized in Earnings
Amount of Gain or (Loss) Recognized in Earnings	$ 9,650	$ (8,278)	$ (3,715)	$ (9,919)
Commodity Derivatives | Nondesignated
Amount of Gain or (Loss) Recognized in Earnings
Amount of Gain or (Loss) Recognized in Earnings	$ 9,650	$ (8,278)	$ (3,715)	$ (9,919)