Stock-Based Compensation

6 Months Ended

Nov. 30, 2013

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

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

10. 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 November 30,				Six months ended November 30,
	2013		2012		2013		2012
Stock option expense	$	4.4	$	0.6	$	4.6	$	1.6
Restricted stock unit expense		1.2		0.8		1.9		1.8
Management stock purchase plan		0.0		0.6		0.1		0.6
Employee stock purchase plan		0.0		0.1		0.1		0.2
Total stock-based compensation expense	$	5.6	$	2.1	$	6.7	$	4.2

During each of the six month periods ended November 30, 2013 and 2012, shares of Common Stock issued by the Corporation pursuant to its stock-based compensation plans were not material.