PENSION PLANS (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25,093	$ 25,100	$ 26,873
Interest cost	25,895	30,495	30,050
Expected return on plan assets	(53,552)	(54,101)	(54,629)
Prior service cost	(100)	(46)	618
Recognized net actuarial loss	12,925	12,029	16,890
Curtailment charge	327		7,461
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	10,588	13,477	27,263
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	435	338	286
Interest cost	762	996	842
Prior service cost	(656)	(657)	(657)
Recognized net actuarial loss	(223)	(296)	(551)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 318	$ 381	$ (80)