Stock-Based Incentive Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Equity classified awards expense	$ 11.6	$ 12.6	$ 10.9
Liability classified awards expense	2.3	1.0	3.2
Total pretax stock-based compensation expense	13.9	13.6	14.1
Book income tax benefit	(3.5)	(3.4)	(3.5)
Total stock-based compensation expense, net of tax	$ 10.4	$ 10.2	$ 10.6