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ACQUISITIONS AND DISPOSITIONS - Purchase Price Allocation - Vibrant Energy (Details) - USD ($) $ in Thousands	Apr. 07, 2016	Apr. 07, 2016	Mar. 31, 2017	Dec. 31, 2016
Purchase price allocation:
Goodwill			$ 62,873	$ 62,873
Vibrant Energy
Purchase price allocation:
Cash	$ 136	$ 136
Prepayments and other assets	636	636
Property, plant and equipment	7,321	7,321
Goodwill	3,279	3,279
Accounts payable and accrued liabilities	(5,179)	(5,179)
Net assets acquired	6,193	6,193
Consideration Transferred
Total consideration	6,193
Cash consideration		3,500
Contingent Consideration	$ 2,700	$ 2,700