Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil and natural gas sales	$ 1,113,852	$ 633,850
Gain on natural gas derivatives, net	10,174	46,858
Crude oil and natural gas service operations	17,002	4,719
Total revenues	1,141,028	685,427
Transportation expenses	49,297	0
Net income	233,946	$ 469
Previous Revenue Recognition
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil and natural gas sales	1,064,555
Gain on natural gas derivatives, net	10,174
Crude oil and natural gas service operations	17,002
Total revenues	1,091,731
Transportation expenses	0
Net income	233,946
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil and natural gas sales	49,297
Gain on natural gas derivatives, net	0
Crude oil and natural gas service operations	0
Total revenues	49,297
Transportation expenses	49,297
Net income	$ 0