Share-Based Compensation - Compensation Expense for Share-Based Awards (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 12.3	$ 11.6
Income tax benefit	(3.1)	(2.9)
Share-based compensation expense, net of tax benefit	9.2	8.7
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	9.2	8.6
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 3.1	$ 3.0