EMPLOYEE BENEFIT PLANS (Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 36,300
Service cost	36,359	$ 24,298	$ 19,407
Interest cost	3,096	2,974	2,404
Expected return on plan assets	(4,681)	(3,422)	(2,156)
Amortization of prior service costs	53	53	39
Amortization of loss	1,043	1,228	1,033
Net periodic benefit cost	35,870	25,131	20,727
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,047	967	1,099
Interest cost	528	558	520
Expected return on plan assets	0	0	0
Amortization of prior service costs	541	326	258
Amortization of loss	0	0	(4)
Net periodic benefit cost	$ 2,116	$ 1,851	$ 1,873