Summary of Significant Accounting Policies - Summary of Property and Equipment Including Oil and Natural Gas Properties (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Oil and natural gas properties:
Unproved properties	$ 478,644	$ 508,576
Proved properties	2,885,622	2,783,232
Gross oil and natural gas properties	3,364,266	3,291,808
Less accumulated depreciation, depletion and amortization	(1,668,786)	(1,532,127)
Total oil and natural gas properties, net	1,695,480	1,759,681
Other property and equipment	19,596	20,000
Less accumulated depreciation	(9,285)	(8,774)
Other property and equipment, net	10,311	11,226
Total property and equipment, net	$ 1,705,791	$ 1,770,907