EMPLOYEE BENEFIT PLANS (Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 16,700
Service cost	24,298	$ 19,407	$ 14,794
Interest cost	2,974	2,404	992
Expected return on plan assets	(3,422)	(2,156)	(550)
Amortization of prior service costs	53	39	11
Amortization of loss	1,228	1,033	421
Net periodic benefit cost	25,131	20,727	15,668
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	967	1,099	726
Interest cost	558	520	334
Expected return on plan assets	0	0	0
Amortization of prior service costs	326	258	0
Amortization of loss	0	(4)	0
Net periodic benefit cost	$ 1,851	$ 1,873	$ 1,060