Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Stock-based compensation cost by award type follows:


(in millions)	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock option awards	$	2.3	$	2.3	$	5.9	$	5.5
Restricted stock awards	1.7		1.8		3.9		3.8
Performance share awards	1.8		1.5		4.3		3.5
Restricted stock units	—		—		—		1.4
Stock appreciation rights	5.9		(0.4)		9.0		(3.4)
Total stock-based compensation cost incurred	11.7		5.2		23.1		10.8
Capitalized (cost) credit during the period	(5.9)		0.2		(9.3)		2.9
Amortization of capitalized cost (credit) during the period	8.8		(3.3)		14.3		0.2
Total stock-based compensation expense	$	14.6	$	2.1	$	28.1	$	13.9