Derivative Financial Instruments (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	$ 2,334	$ (4,321)	$ 9,286
Unrealized gain (loss) on derivatives	65,085	9,715	(41,238)
Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	2,334	(4,321)	9,286
Unrealized gain (loss) on derivatives	65,085	9,715	(41,238)
Total	67,419	5,394	(31,952)
Oil | Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	3,741	(3,657)	5,851
Unrealized gain (loss) on derivatives	65,991	2,638	(18,969)
Natural Gas | Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	(1,407)	(608)	3,435
Unrealized gain (loss) on derivatives	(906)	7,077	(22,269)
NGLs | Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	$ 0	$ (56)	$ 0