EMPLOYEE BENEFIT PLANS (Pre-tax Amounts Recognized in Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service costs	$ 0	$ 462	$ 0
Net actuarial loss (gain)	1,877	5,015	176
Amortization of losses and prior service cost	(826)	(1,410)	(1,096)
Total changes in other comprehensive income (loss)	1,051	4,067	(920)
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service costs	0	0	2,524
Net actuarial loss (gain)	(3,388)	(2,471)	1,487
Amortization of losses and prior service cost	(646)	(646)	(541)
Total changes in other comprehensive income (loss)	$ (4,034)	$ (3,117)	$ 3,470