v3.19.1

INVENTORY AND LONG-TERM PARTS INVENTORY (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Inventory [Line Items] |  |  |  |  |  |  |  |  |  |  |
Lower of cost or net realizable value inventory adjustments | $ 930 | $ 0 | $ 76 | $ 705 | $ 1,571 | $ 666 | $ 317 | $ 3,825 | $ 1,711 | $ 6,379 | $ 20,374
Costs associated with abnormal production and other |  |  |  |  |  |  |  |  |  |  | 1,707
East Facility [Member] |  |  |  |  |  |  |  |  |  |  |
Inventory [Line Items] |  |  |  |  |  |  |  |  |  |  |
Costs associated with abnormal production and other |  |  |  |  |  |  |  |  |  |  | $ 1,707

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