Summary of Significant Accounting Policies - Summary of Property and Equipment Including Oil and Natural Gas Properties (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Oil and natural gas properties:
Unproved properties	$ 492,058	$ 526,270
Proved properties	1,749,430	1,545,860
Gross oil and natural gas properties	2,241,488	2,072,130
Less accumulated depreciation depletion and amortization	(1,181,706)	(1,131,378)
Total oil and natural gas properties, net	1,059,782	940,752
Other property and equipment	11,983	11,447
Less accumulated depreciation	(5,712)	(4,699)
Other property and equipment, net	6,271	6,748
Total property and equipment, net	$ 1,066,053	$ 947,500