Stock-Based Compensation (Tables)

6 Months Ended

Nov. 30, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan

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

	Three months ended				Six months ended
	November 30,				November 30,
	2023		2022		2023		2022
Stock option expense	$	2.4	$	2.4	$	3.0	$	3.0
Restricted stock unit expense		1.4		1.3		2.9		2.3
Management stock purchase plan		0.3		0.4		0.3		0.4
Employee stock purchase plan		0.0		0.1		0.2		0.2
Total stock-based compensation expense	$	4.1	$	4.2	$	6.4	$	5.9

Schedule of Shares Issued Pursuant to Share-based Compensation Activity

The following table sets forth Common Stock issued pursuant to stock-based compensation plans for the periods indicated:

	Three months ended		Six months ended
	November 30,		November 30,
	2023	2022	2023	2022
Common Stock issued pursuant to stock-based compensation plans (in millions)	0.3	0.3	0.4	0.6