PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Detail) - Pension Plans Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,495	$ 6,474	$ 13,001	$ 12,945
Interest cost	6,521	6,236	13,055	12,455
Expected return on plan assets	(14,695)	(13,310)	(29,411)	(26,595)
Amortization of prior service cost	(62)	(26)	(125)	(51)
Amortization of unrecognized actuarial loss	3,903	3,585	7,809	7,166
Net postretirement benefit cost (income)	$ 2,162	$ 2,959	4,329	$ 5,920
Defined Benefit Plan, Plan Assets, Contributions by Employer			$ 50,000