EMPLOYEE BENEFIT PLANS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,699	$ 3,548	$ 7,397	$ 5,718
Interest cost	248	215	496	251
Expected return on plan assets	(138)	(152)	(276)	(162)
Amortization of prior service costs	3	2	5	5
Amortization of loss	105	1	210	15
Net periodic benefit cost	3,917	3,614	7,832	5,827
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	181	135	363	270
Interest cost	84	95	167	190
Net periodic benefit cost	$ 265	$ 230	$ 530	$ 460