Derivative Financial Instruments (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized (loss) gain on derivatives	$ (2,488)	$ 558	$ (6,746)	$ (1,661)
Unrealized gain on derivatives	1,429	13,190	11,845	33,821
Total	(1,059)	13,748	5,099	32,160
Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized (loss) gain on derivatives	(2,488)	558	(6,746)	(1,661)
Unrealized gain on derivatives	1,429	13,190	11,845	33,821
Oil | Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized (loss) gain on derivatives	(2,488)	581	(6,797)	(1,053)
Unrealized gain on derivatives	1,829	10,643	12,956	28,422
Natural Gas | Revenues
Summary of location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations
Realized (loss) gain on derivatives	0	(23)	51	(608)
Unrealized gain on derivatives	$ (400)	$ 2,547	$ (1,111)	$ 5,399