Treasury Stock (Details) - Schedule of repurchase of common stock - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended			23 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015	May 31, 2017	Jul. 22, 2015
Class of Stock [Line Items]
Stock Repurchase Program, Increase in Authorized Amount					$ 50.0
Amount of stock repurchased in period	$ 6.9	$ 14.4	$ 3.5	$ 11.4
Remaining authorized repurchase amount	$ 38.6			$ 38.6
Shares of stock repurchased (in shares)	0.2
Average cost of stock repurchased (in Dollars per share)	$ 38.80
Common Stock [Member]
Class of Stock [Line Items]
Common Stock, par value per share (in Dollars per share)	$ 0.01	$ 0.01		$ 0.01