Derivative Financial Instruments (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized gain (loss) on derivatives	$ 3,270	$ (4,258)
Unrealized (loss) gain on derivatives	(45,719)	10,416
Total	(42,449)	6,158
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	3,270	(4,258)
Unrealized (loss) gain on derivatives	(45,719)	10,416
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	3,366	(4,309)
Unrealized (loss) gain on derivatives	(45,444)	11,127
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	(96)	51
Unrealized (loss) gain on derivatives	$ (275)	$ (711)