v3.8.0.1
INVENTORY AND LONG-TERM PARTS INVENTORY (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Inventory Disclosure [Abstract]          
Inventory valuation reserves $ 3,100   $ 3,100   $ 3,100
Lower-of-cost-or-market inventory adjustments 667 $ 5,192 4,808 $ 17,129  
Production Related Impairments or Charges $ 0 $ 0 $ 0 $ 1,707