Stock-Based Compensation (Tables)

3 Months Ended

Nov. 30, 2012

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

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,
	2012		2011		2012		2011
Stock option expense	$	0.6	$	3.4	$	1.6	$	4.8
Restricted stock unit expense		0.8		2.0		1.8		2.6
Management stock purchase plan		0.6		0.2		0.6		0.2
Employee stock purchase plan		0.1		0.1		0.2		0.2
Total stock-based compensation expense	$	2.1	$	5.7	$	4.2	$	7.8