Impairment of Assets - Additional Information (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($) Rig	Mar. 31, 2020 USD ($) Rig	Jun. 30, 2020 USD ($)
Schedule Of Asset Impairment Charges [Line Items]
Impairment of assets \| $		$ 774,000,000.0	$ 774,028,000
2020 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment \| Rig	4	5
Impairment of assets \| $	$ 0		$ 774,000,000.0
Number of rigs impaired during period \| Rig		4

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

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