EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 10,900	$ 11,900	$ 32,700	$ 35,500
Interest cost	2,000	1,500	6,200	4,300
Expected return on plan assets	(2,300)	(2,200)	(7,100)	(6,400)
Amortization of prior service cost and actuarial loss	100	100	200	300
Net periodic benefit cost	10,700	11,300	32,000	33,700
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	200	400	700	900
Interest cost	200	100	500	500
Amortization of prior service cost and actuarial loss	100	200	400	500
Net periodic benefit cost	$ 500	$ 700	$ 1,600	$ 1,900