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ACQUISITIONS - BLUEWATER ACQUISITION - CONSIDERATION TRANSFERRED (Details) - Bluewater - USD ($) $ in Millions | 1 Months Ended |
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Jun. 30, 2017 | Sep. 30, 2018
Business Acquisition [Line Items] |  |
Purchase price | $ 226.0 |
Percentage of current storage needs provided |  | 33.00%
Acquisition related costs | $ 4.9 |

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