FAIR VALUE (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Other long-term assets	$ 4,708	$ 5,038
Recurring basis | Level 1
Assets
Pension plan assets	5,603	5,231
Other long-term assets	4,340	3,962
Recurring basis | Level 2
Assets
Interest rate swaps	$ 223	$ 434