BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value Accounting (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets (liabilities)
Other long-term assets	$ 4,835	$ 5,038
Recurring basis | Level 1
Assets (liabilities)
Pension plan assets	6,099	5,231
Other long-term assets	4,690	3,962
Recurring basis | Level 2
Assets (liabilities)
Interest rate swaps/liabilities	$ (363)
Interest rate swaps/assets		$ 434