Stock-Based Compensation - Allocation of Share-based Compensation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	$ 23.3	$ 23.7	$ 37.5
Stock option and appreciation rights
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	11.3	5.6	12.5
Performance share units, stock-settled
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	5.5	15.6	17.6
Performance share units, cash-settled
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	0.3	(0.1)	1.0
Performance share units, dividend equivalents
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	0.1	0.1	0.2
Employee stock purchase plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	1.3	1.3	1.4
Deferred compensation plans and restricted share awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock compensation expense	$ 4.8	$ 1.2	$ 4.8