Commitments and Contingencies - Additional Information - Legal Proceedings and Claims - Polar Spirit contract termination (Details) $ in Millions	1 Months Ended
Dec. 31, 2016 USD ($)
Polar Spirit [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	$ 42.4

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.

No definition available.

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