Summary of Significant Accounting Policies - Summary of Property and Equipment Including Oil and Natural Gas Properties (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Oil and natural gas properties:
Unproved properties	$ 684,383	$ 720,159
Proved properties	1,338,546	1,288,609
Gross oil and natural gas properties	2,022,929	2,008,768
Less accumulated depreciation depletion and amortization	(1,075,477)	(1,022,771)
Total oil and natural gas properties, net	947,452	985,997
Other property and equipment	11,169	10,753
Less accumulated depreciation	(3,746)	(2,782)
Other property and equipment, net	7,423	7,971
Total property and equipment, net	$ 954,875	$ 993,968