PENSION AND POST-RETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (income) costs	$ 0.6	$ (0.1)	$ 1.5
Estimated contributions in next fiscal year	10.0
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial losses and prior service costs expected to be recognized in net periodic benefit cost during next fiscal year			$ 2.4
Net periodic benefit (income) costs	0.4	(0.3)
Employer contributions	1.6
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (income) costs	0.2	$ 0.2
Employer contributions	$ 0.2