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Revenue Recognition - Additional Information (Detail) - Vessel Mobilization $ in Millions | Mar. 31, 2018 USD ($)
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Disaggregation Of Revenue [Line Items] |
Deferred costs included within other current assets | $ 0.4
Deferred capital modification revenue included within other current liabilities | $ 1.9

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- Definition Amount of deferred cost assets and assets classified as other. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Carrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income during the current period and current obligations not separately disclosed in the balance sheet (other liabilities, current). + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- 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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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |