Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of stock-based compensation expense

Stock-based compensation expense for the three and nine months ended September 30, 2021 and 2020 is shown in the table below (in millions):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Stock options	$	0.4	$	0.7	$	1.5	$	2.0
Time-based restricted share units	2.5		1.8		6.8		4.2
Performance-based restricted share units	0.5		0.8		1.7		2.5
Employee stock purchase plan	0.1		0.1		0.2		0.2
Total stock-based compensation	$	3.5	$	3.4	$	10.2	$	8.9