Derivative Commodity Instruments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Gain on fair value of derivatives	$ 38,101	$ (65,872)	$ 102,647	$ (60,417)
Commodity contracts | PNC Bank
Derivative [Line Items]
Gain on fair value of derivatives			6,400
Commodity contracts | J.P. Morgan Ventures Energy Corporation.
Derivative [Line Items]
Gain on fair value of derivatives			6,000
Commodity contracts | J Aron And Company
Derivative [Line Items]
Gain on fair value of derivatives			$ 5,100