Share-Based Compensation - Compensation Expense for Share-Based Awards (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 7.2	$ 6.8	$ 28.7	$ 26.9
Income tax benefit	(1.8)	(1.7)	(7.2)	(6.8)
Share-based compensation expense, net of tax benefit	5.4	5.1	21.5	20.1
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	4.1	3.9	18.7	18.4
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 3.1	$ 2.9	$ 10.0	$ 8.5