CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 96.2	$ 45.0	$ 165.3	$ 140.8
Other comprehensive (loss) income:
Change in fair value of cash flow swaps	0.0	(1.0)	(5.1)	(5.3)
Income tax benefit associated with cash flow swaps	0.0	0.3	1.3	1.4
Comprehensive income	$ 96.2	$ 44.3	$ 161.5	$ 136.9