EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5,790	$ 5,134	$ 17,369	$ 14,276
Interest cost	710	616	2,126	1,787
Expected return on plan assets	(830)	(546)	(2,489)	(1,609)
Amortization of prior service costs	13	13	39	26
Amortization of loss	311	277	933	757
Net periodic benefit cost	5,994	5,494	17,978	15,237
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	243	269	731	747
Interest cost	134	125	403	353
Amortization of prior service costs	76	52	228	107
Amortization of loss	0	0	0	(4)
Net periodic benefit cost	$ 453	$ 446	$ 1,362	$ 1,203