Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Nov. 30, 2017	Aug. 31, 2017	Oct. 31, 2016
Equity [Abstract]
Shares repurchase authorized amount		$ 160.0	$ 40.0
Shares acquired through stock repurchase program	1.7	6.7
Purchase of treasury stock	$ 40.8	$ 172.9
Weighted-average price per share	$ 24.51	$ 25.71
Remaining amount authorized for repurchase through share repurchase program	$ 119.2