EMPLOYEE BENEFIT PLANS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,699	$ 2,170
Interest cost	248	35
Expected return on plan assets	(138)	(10)
Amortization of prior service costs	3	3
Amortization of loss	105	14
Net periodic benefit cost	3,917	2,212
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	181	135
Interest cost	84	95
Net periodic benefit cost	$ 265	$ 230