Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Line Items]
Goodwill	$ 0			$ 0
Goodwill impairment charge					$ 395,060,000
Amortization expense on intangible assets	$ 3,100,000	$ 5,300,000		$ 6,300,000	$ 10,600,000
Contract Drilling
Goodwill And Intangible Assets Disclosure [Line Items]
Goodwill impairment charge			$ 395,000,000