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Interim Financial Statements - Additional Information (Detail) | 2 Months Ended | 4 Months Ended | 6 Months Ended
--- | --- | --- | ---
Sep. 30, 2017 | Jul. 31, 2017 | Sep. 30, 2017
Reorganizations [Line Items] |  |  |
Prepackaged plan of reorganization, date of written order issued by court |  |  | Jul. 17, 2017
Prepackaged plan of reorganization, petition date |  |  | May 17, 2017
Prepackaged plan of reorganization, date on emerged from bankruptcy |  |  | Jul. 31, 2017
Court where petition for bankruptcy was filed |  |  | United States Bankruptcy Court for the District of Delaware (the “Bankruptcy Court”)
Planned major maintenance activities, comprehensive surveys to maintain certifications for vessels, consecutive period | 5 years |  |
Costs related to recertification of vessels deferred and amortized, period | 30 months |  |
Vessels |  |  |
Reorganizations [Line Items] |  |  |
Estimated useful lives | 20 years |  |
Percentage of salvage values | 7.50% |  | 7.50%
Predecessor | Vessels |  |  |
Reorganizations [Line Items] |  |  |
Estimated useful lives |  | 25 years |
Percentage of salvage values |  | 10.00% |

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