EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Amortization of:
Contribution to pension plans			$ 19,000
Estimated total contributions	$ 28,000		28,000
Pension Benefits
Amortization of:
Net pension expense	6,710	$ 12,550	13,692	$ 25,907
Union Administered Plan | Pension Benefits
Amortization of:
Net pension expense	2,524	2,621	4,870	5,123
Company Administered Plan | Pension Benefits
Components of net periodic benefit cost
Service cost	3,095	3,017	6,296	6,266
Interest cost	19,098	21,426	38,850	42,915
Expected return on plan assets	(25,065)	(22,712)	(50,899)	(45,190)
Amortization of:
Net actuarial loss	6,914	8,077	14,286	16,527
Prior service cost	144	121	289	266
Net pension expense	4,186	9,929	8,822	20,784
U.S. | Company Administered Plan | Pension Benefits
Amortization of:
Net pension expense	6,665	10,547	14,022	21,858
Non-U.S. | Company Administered Plan | Pension Benefits
Amortization of:
Net pension expense	$ (2,479)	$ (618)	$ (5,200)	$ (1,074)