Summary of Significant Accounting Policies - Summary of Lease Cost Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020
Operations And Summary Of Significant Accounting Policies [Line Items]
Operating lease cost	$ 7,975	$ 28,432
General and Administrative Expense
Operations And Summary Of Significant Accounting Policies [Line Items]
Operating lease cost	422	1,249
Lease Operating Expense
Operations And Summary Of Significant Accounting Policies [Line Items]
Operating lease cost	229	578
Short-term Drilling Rig Costs Included in Proved Oil and Gas Properties
Operations And Summary Of Significant Accounting Policies [Line Items]
Operating lease cost	$ 7,324	$ 26,605

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration