Stock-Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2.4	$ 5.3
Stock Appreciation Rights
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	(1.5)	1.7
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	0.1	0.0
Restricted stock and restricted stock units, service based
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1.5	1.2
Restricted stock and restricted stock units, performance based
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2.0	2.2
Employee stock purchase plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 0.3	$ 0.2