Share-Based Compensation - Compensation Expense for Share-Based Awards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 40.0	$ 35.6	$ 35.5
Income tax benefit	(10.0)	(8.9)	(8.9)
Impact on net income	30.0	26.7	26.6
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	25.5	22.5	23.0
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 14.5	$ 13.1	$ 12.5