ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	$ 961.2	$ 805.7
Amortization of prior service cost	(1.1)	(1.2)
Amortization of net loss	1.2	1.3
Other adjustments	(0.2)	(0.7)
Balance at the end of the period	1,028.9	800.2
Pensions
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(61.7)	(51.9)
Amortization of prior service cost	(0.4)	(0.5)
Amortization of net loss	0.9	1.1
Balance at the end of the period	(61.2)	(51.3)
Post Retirement
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	12.2	16.3
Amortization of prior service cost	(0.7)	(0.6)
Amortization of net loss	0.2	0.1
Balance at the end of the period	11.7	15.8
Non-Qualified Plans
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(0.6)	(0.4)
Amortization of prior service cost		(0.1)
Amortization of net loss	0.1	0.1
Balance at the end of the period	(0.5)	(0.4)
Other
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(0.7)	(0.9)
Foreign currency exchange	(0.2)	(0.5)
Other adjustments		(0.2)
Balance at the end of the period	(0.9)	(1.6)
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(50.8)	(36.9)
Amortization of prior service cost	(1.1)	(1.2)
Amortization of net loss	1.2	1.3
Foreign currency exchange	(0.2)	(0.5)
Other adjustments		(0.2)
Balance at the end of the period	$ (50.9)	$ (37.5)