FINANCIAL INSTRUMENTS AND FAIR VALUE FINANCIAL INSTRUMENTS AND FAIR VALUE (Narrative) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2015	Nov. 30, 2013
Fair Value, Inputs, Level 2 | Other Long-term Liabilities and Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of interest rate swaps	$ (3,200,000)	$ (1,700,000)
New Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional principal amount of derivative liability	86,400,000.0		$ 100,000,000
Notional principal amount of derivative liability, at maturity			$ 53,100,000
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional principal amount of derivative liability	57,400,000.0			$ 75,000,000
Notional principal amount of derivative liability, at maturity				$ 38,700,000
Fair value of interest rate swaps	(3,200,000)	$ 1,700,000
Interest rate swap, net loss amount expected to be reclassified in the next twelve months	$ (300,000)