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		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Net Earnings Per Common Share
Net earnings (loss)	$ 19.8	$ (400.8)	$ 35.6	$ (375.5)
Basic weighted average common shares (in millions)	51.8	52.2	51.9	52.2
Effect of dilutive securities - dilutive securities	0.4		0.3
Diluted weighted average common shares (in millions)	52.2	52.2	52.2	52.2
Basic net earnings (loss) per share	$ 0.38	$ (7.68)	$ 0.69	$ (7.19)
Diluted net earnings (loss) per share	$ 0.38	$ (7.68)	$ 0.68	$ (7.19)