Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock-Based Compensation Expense by Type of Award

Total stock-based compensation expense by type of award was as follows:

	Three months ended September 30,					Nine months ended September 30,
	2017		2016			2017		2016
	(In millions)
Stock appreciation rights	$	8.3	$	(0.3	)	$	10.7	$	1.6
Stock options	0.3		0.3			1.0		0.6
Restricted shares, service based	0.9		0.9			3.3		2.5
Restricted shares, performance based	1.3		1.3			5.7		2.7
Employee stock purchase plan	0.2		0.1			0.5		0.3
Total stock-based compensation expense	$	11.0	$	2.3		$	21.2	$	7.7