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Related Party Transactions - Operating Activities - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Related Party Transaction [Line Items]
Vessel and rig operating expenses	$ 407.0	$ 437.0
Contract Revenue Cost [Member] | Archer [Member] | Equity Method Investee [Member]
Related Party Transaction [Line Items]
Vessel and rig operating expenses	$ 0.1	$ 0.2

X

- Definition

Costs incurred and are directly related to generating contract revenues.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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X

- Details

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X

- Details

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X

- Details

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