Net Earnings Per Common Share (Computations of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Net Loss Per Common Share
Net loss	$ (243.1)	$ (5.0)
Basic weighted average common shares	23.1	21.2
Diluted weighted average common shares	23.1	21.2
Basic net loss per common share (in dollars per share)	$ (10.52)	$ (0.24)
Diluted net loss per common share (in dollars per share)	$ (10.52)	$ (0.24)