Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Compensation Expense

Stock-based compensation cost by award type follows:

(in millions)	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Stock option awards	$	2.6	$	3.2	$	8.2	$	7.8
Restricted stock awards	1.7		2.3		5.8		6.4
Performance share awards	1.4		2.2		4.5		6.1
Restricted stock units	—		—		1.3		1.4
Stock appreciation rights	2.1		—		5.0		—
Total stock-based compensation cost	$	7.8	$	7.7	$	24.8	$	21.7