Stock-Based Compensation - Allocation of Share-based Compensation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 37.5	$ 34.0	$ 24.4
Stock option and appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	12.5	10.2	9.1
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	17.6	16.6	9.5
Cash-Settled PSU Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	1.0	0.4	0.1
Performance-vesting Shares or Units Dividend Equivalents
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	0.2	0.6	0.2
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	1.4	1.1	0.9
Deferred Compensation, Share-based Payments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 4.8	$ 5.1	$ 4.6