Stock-Based Compensation

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation

Stock-Based Compensation

Stock-based compensation cost by award type follows:

(in millions)	Three Months Ended March 31,
	2021		2020
Stock option awards	$	3.8	$	3.2
Restricted stock awards	2.2		2.1
Performance share awards	2.5		2.1
Restricted stock units	—		1.4
Stock appreciation rights	3.9		(3.6)
Total stock-based compensation cost incurred	12.4		5.2
Capitalized (cost) credit during the period	(4.3)		3.3
Amortization of capitalized cost during the period	6.8		4.2
Total stock-based compensation expense	$	14.9	$	12.7