EMPLOYEE BENEFIT PLANS (Pre-tax Amounts Recognized in Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service costs (credits)	$ 462	$ 0	$ 0
Net actuarial loss (gain)	5,015	176	(2,220)
Amortization of loss	(1,410)	(1,096)	(1,281)
Total changes in other comprehensive loss (income)	4,067	(920)	(3,501)
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service costs (credits)	0	2,524	1,533
Net actuarial loss (gain)	(2,471)	1,487	312
Amortization of loss	(646)	(541)	(326)
Total changes in other comprehensive loss (income)	$ (3,117)	$ 3,470	$ 1,519