Stock-Based Compensation (Tables)

3 Months Ended

Aug. 31, 2013

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

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
	August 31, 2013		August 31, 2012
Stock option expense	$	0.2	$	1.0
Restricted stock unit expense		0.8		0.9
Management stock purchase plan		0.0		0.0
Employee stock purchase plan		0.1		0.1
Total stock-based compensation expense	$	1.1	$	2.0