FAIR VALUE (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets (liabilities)
Other long-term assets	$ 4,618	$ 5,038
Recurring basis | Level 1
Assets (liabilities)
Pension plan assets	5,773	5,231
Other long-term assets	4,471	3,962
Recurring basis | Level 2
Assets (liabilities)
Interest rate swaps	$ (264)	$ 434