Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 1,500,000	$ 1,500,000
Capitalized exploratory drilling costs pending evaluation	0	0
Amortization expense including write-off of debt issuance costs	3,300,000	1,200,000
Impairment expense for proved/unproved properties	476,936,000	2,246,000
Capitalized interest	$ 200,000	200,000
Chance of tax benefit likely to be realized	greater than 50%
Proved Developed and Producing Oil and Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment expense for proved/unproved properties	$ 427,600,000	0
Unproved Oil and Natural Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment expense for unproved leasehold costs	$ 49,300,000	$ 2,200,000
Minimum [Member] | Other Property & Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Support Equipment and Facilities [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	12 years
Maximum [Member] | Other Property & Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Support Equipment and Facilities [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	24 years
Customer Concentration Risk [Member] | Revenues [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of total revenue	10.00%