PENSION AND POST-RETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (income) costs	$ 0.8	$ 0.8	$ 2.0	$ 1.9	$ 1.5
Estimated contributions in next fiscal year	10.0		10.0
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (income) costs	0.6	0.7	1.4	1.4
Actuarial losses and prior service costs expected to be recognized in net periodic benefit cost during next fiscal year	2.7		2.7
Employer contributions	2.1		5.5
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	$ 0.1	0.6	$ 0.5
Employer contributions	$ 0.2		$ 0.6