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