Stock-Based Compensation

9 Months Ended

Feb. 28, 2018

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

Stock-Based Compensation

STOCK-BASED COMPENSATION

The following table summarizes stock-based compensation expense included in Selling, general and administrative expenses for the periods indicated: 

	Three months ended February 28,				Nine months ended February 28,
	2018		2017		2018		2017
Stock option expense	$	0.8	$	0.9	$	6.2	$	6.0
Restricted stock unit expense	0.6		0.6		2.0		2.0
Management stock purchase plan	0.1		0.1		0.7		0.5
Employee stock purchase plan	0.1		0.0		0.2		0.2
Total stock-based compensation expense	$	1.6	$	1.6	$	9.1	$	8.7

The following table sets forth Common Stock issued pursuant to stock-based compensation plans as of the dates indicated:

	Three months ended February 28,		Nine months ended February 28,
	2018	2017	2018	2017
Common Stock issued pursuant to stock-based compensation plans (in millions)	0.2	0.4	0.4	0.7