ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary of Unrealized Gains (Losses) on Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment Out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Tax benefit	$ (7.2)	$ (6.0)	$ 2.9	$ (19.8)
Net of tax	1.2	(0.4)	(3.0)	(4.7)
Interest Rate Contract
Reclassification Adjustment Out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized gain (loss) on derivative instruments	0.0	(0.9)	(7.6)	(6.9)
Loss on derivatives reclassified into income	1.6	0.3	3.5	0.5
Total before tax	1.6	(0.6)	(4.1)	(6.4)
Tax benefit	(0.4)	0.2	1.1	1.7
Net of tax	$ 1.2	$ (0.4)	$ (3.0)	$ (4.7)