FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers in (out) between levels	$ 0.0		$ 0.0
Fair value of total debt	123.5	$ 124.8
Carrying amount of long-term debt	122.0	122.7
Investments held in Rabbi Trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities measured at fair value	1.5	1.5
Investments held in Rabbi Trust [Member] | SERP [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross unrealized gains associated with the investment held in the rabbi trust	0.2	0.2
Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets accounted at fair value	$ 0.0	$ 0.0