FAIR VALUE MEASUREMENTS (Fair Value Measurement on Recurring Basis) (Details) - Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value, recurring	$ 20,256	$ 16,916	$ 15,175
Level 1 [Member] | Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value, recurring	7,431	6,883	6,601
Level 1 [Member] | Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value, recurring	12,825	10,033	8,574
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value, recurring	386	1,705	2,144
Level 2 [Member] | Money Market Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value, recurring	$ 386	$ 1,705	$ 2,144