FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accrued and other long term liabilities | LDS
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 6,800
Interest rate swap agreement | Other long-term liabilities
Assets and liabilities measured at fair value on a recurring basis
Interest rate swap	1,600	$ 900
Recurring basis
Assets and liabilities measured at fair value on a recurring basis
Assets	9,875	27,031
Liabilities	8,380
Recurring basis | Accrued and other long term liabilities
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	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	1,605	897
Recurring basis | Money market funds | Cash and cash equivalents
Assets and liabilities measured at fair value on a recurring basis
Assets	7,803	24,904
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	2,072	2,127
Recurring basis | Level 1
Assets and liabilities measured at fair value on a recurring basis
Assets	9,875	27,031
Recurring basis | Level 1 | Money market funds | Cash and cash equivalents
Assets and liabilities measured at fair value on a recurring basis
Assets	7,803	24,904
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	2,072	2,127
Recurring basis | Level 2
Assets and liabilities measured at fair value on a recurring basis
Liabilities	1,605
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	1,605	$ 897
Recurring basis | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liabilities	$ 6,775
Recurring basis | Level 3 | LDS
Assets and liabilities measured at fair value on a recurring basis
Discount rate (as a percent)	11.50%
Recurring basis | Level 3 | Accrued and other long term liabilities
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 6,775