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Comparison of Total Assets (Parenthetical) (Detail) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2017 | Mar. 31, 2017
Corporate Vessels |  |
Segment and Geographic Distribution of Operations [Line Items] |  |
Construction costs | $ 7.0 | $ 52.4

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- Definition The aggregate costs related to construction and development services during the reporting period. + 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) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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