Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Oil and natural gas properties
Evaluated (subject to amortization)	$ 3,004,770	$ 2,408,305
Total unproved and unevaluated	637,396	479,736
Total oil and natural gas properties	3,642,166	2,888,041
Accumulated depletion	(2,021,169)	(1,850,882)
Net oil and natural gas properties	1,620,997	1,037,159
Other property and equipment
Midstream and other property and equipment	281,096	160,795
Accumulated depreciation	(20,637)	(13,429)
Net other property and equipment	260,459	147,366
Net property and equipment	1,881,456	1,184,525
Midstream equipment and facilities
Other property and equipment
Midstream and other property and equipment	258,725	145,662
Furniture, fixtures and other equipment
Other property and equipment
Midstream and other property and equipment	6,109	5,487
Software
Other property and equipment
Midstream and other property and equipment	7,942	3,206
Land
Other property and equipment
Midstream and other property and equipment	2,892	1,437
Leasehold improvements
Other property and equipment
Midstream and other property and equipment	$ 5,428	$ 5,003