FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Assets and Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Interest rate swap agreement | Other long-term liabilities
Assets and liabilities measured at fair value on a recurring basis
Interest rate swap	$ 300	$ 500
Recurring basis
Assets and liabilities measured at fair value on a recurring basis
Assets	22,879	7,923
Liabilities	7,109	7,317
Recurring basis | Accrued and other long term liabilities
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	6,790	6,775
Recurring basis | Interest rate swap agreement | Other long-term liabilities
Assets and liabilities measured at fair value on a recurring basis
Interest rate swap	319	542
Recurring basis | Money market funds | Cash and cash equivalents
Assets and liabilities measured at fair value on a recurring basis
Assets	20,608	5,703
Recurring basis | Voluntary Savings Plan - mutual funds held in trust | Other long-term assets
Assets and liabilities measured at fair value on a recurring basis
Assets	2,271	2,220
Recurring basis | Level 1
Assets and liabilities measured at fair value on a recurring basis
Assets	22,879	7,923
Recurring basis | Level 1 | Money market funds | Cash and cash equivalents
Assets and liabilities measured at fair value on a recurring basis
Assets	20,608	5,703
Recurring basis | Level 1 | Voluntary Savings Plan - mutual funds held in trust | Other long-term assets
Assets and liabilities measured at fair value on a recurring basis
Assets	2,271	2,220
Recurring basis | Level 2
Assets and liabilities measured at fair value on a recurring basis
Liabilities	319	542
Recurring basis | Level 2 | Interest rate swap agreement | Other long-term liabilities
Assets and liabilities measured at fair value on a recurring basis
Interest rate swap	319	542
Recurring basis | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liabilities	$ 6,790	6,775
Recurring basis | Level 3 | LDS
Assets and liabilities measured at fair value on a recurring basis
Discount rate (as a percent)	12.30%
Recurring basis | Level 3 | Accrued and other long term liabilities
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 6,790	$ 6,775