Summary of Significant Accounting Policies - Summary of Property and Equipment Including Oil and Natural Gas Properties (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Oil and natural gas properties:
Unproved properties	$ 520,941	$ 482,475
Proved properties	2,702,202	2,188,233
Gross oil and natural gas properties	3,223,143	2,670,708
Less accumulated depreciation, depletion and amortization	(1,491,326)	(1,380,650)
Total oil and natural gas properties, net	1,731,817	1,290,058
Other property and equipment	21,935	14,460
Less accumulated depreciation	(9,586)	(8,160)
Other property and equipment, net	12,349	6,300
Total property and equipment, net	$ 1,744,166	$ 1,296,358