ACCUMULATED OTHER COMPREHENSIVE LOSS (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Loss [Abstract]
Unrealized losses on derivative instruments, substantially entered into by the Company's equity method joint venture investees	$ (112)	$ (1,019)
Items not yet recognized as a component of net periodic benefit cost (pension and other postretirement benefit plans)	(6,350)	(7,141)
Accumulated other comprehensive loss	$ (6,462)	$ (8,160)