Stockholders' Equity (Computation of Basic and Diluted Net Earnings per Share) (Details) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2015 USD ($) $ / shares shares	Jan. 31, 2017 USD ($) $ / shares	Oct. 31, 2016 USD ($) $ / shares	Jul. 31, 2016 USD ($) $ / shares	Apr. 30, 2016 USD ($) $ / shares	Jan. 31, 2016 USD ($) $ / shares	Oct. 31, 2015 USD ($) $ / shares	Jul. 31, 2015 USD ($) $ / shares	Apr. 30, 2015 USD ($) $ / shares	Jan. 31, 2017 USD ($) $ / shares shares	Jan. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 16, 2014
Stockholders' Equity
Numerator: net (loss) earnings | $	$ 7.1	$ 17.9	$ 19.8	$ 8.0	$ 2.5	$ (10.3)	$ (400.8)	$ 7.4	$ 17.9	$ 48.2	$ (385.8)	$ 88.1
Weighted average common shares:
Basic weighted average common shares (in millions)	52.2									51.8	52.2	52.2
Effect of dilutive securities - Dilutive securities (in millions)	0.1									0.4		0.1
Diluted weighted average common shares (in millions)	52.3									52.2	52.2	52.3
Basic net (loss) earnings per share:
Basic net (loss) earnings per share | $ / shares	$ 0.14	$ 0.35	$ 0.38	$ 0.15	$ 0.05	$ (0.20)	$ (7.68)	$ 0.14	$ 0.34	$ 0.93	$ (7.39)	$ 1.69
Diluted net (loss) earnings per share:
Diluted net (loss) earnings per share | $ / shares	$ 0.14	$ 0.34	$ 0.38	$ 0.15	$ 0.05	$ (0.20)	$ (7.68)	$ 0.14	$ 0.34	$ 0.92	$ (7.39)	$ 1.68
Ratio of shares of KLX received for shares of B/E Aerospace													0.5