PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Additional) (Detail) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Cost	$ 10.0	$ 8.9
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 10.9
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount			$ 11.8