BENEFIT PLANS - THE AMOUNTS IN AOCI THAT ARE EXPECTED TO BE AMORTIZED AS NET EXPENSE (INCOME) DURING NEXT FISCAL YEAR (Details) $ in Millions	Dec. 31, 2017 USD ($)
Pension Plans
Schedule of Pension and Other Postretirment Benefits Expected Benefit Payments [Line Items]
Amount of net prior service credit	$ (0.1)
Amount of net loss	6.5
Total amount to be amortized out of AOCI in 2018	6.4
Other Postemployment Benefits
Schedule of Pension and Other Postretirment Benefits Expected Benefit Payments [Line Items]
Amount of net prior service credit	0.0
Amount of net loss	0.2
Total amount to be amortized out of AOCI in 2018	$ 0.2