Stockholders' Equity - Additions to and Reclassifications out of Accumulated Other Comprehensive (Loss) Earnings (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2018	Apr. 30, 2017
Equity [Abstract]
Foreign currency translation adjustments		$ (25.4)	$ 12.4
Income tax benefit (expense)		0.4	(0.3)
Foreign currency translation adjustments		(25.0)	12.1
Unrealized gain on marketable securities		0.0	0.4
Income tax expense		0.0	(0.3)
Unrealized gain on marketable securities		0.0	0.1
Unrealized loss on hedging instruments		(7.2)	(10.3)
Reclassification adjustment for (gain) loss included in net earnings a	[1]	(2.3)	9.0
Income tax benefit		2.2	0.3
Unrealized loss on hedging instruments		(7.3)	(1.0)
Amortization of net loss included in net earnings b	[2]	3.3	3.5
Amortization of prior service credit included in net earnings	[2]	(0.2)	(0.1)
Income tax expense		(0.7)	(1.2)
Unrealized gain on benefit plans		2.4	2.2
Other comprehensive (loss) earnings, net of tax		$ (29.9)	$ 13.4

[1] aThese (gains) losses are reclassified into Cost of Sales, Interest expense and financing costs and Other expense, net (see "Note 8. Hedging Instruments" for additional details).

[2] bThese accumulated other comprehensive income components are included in the computation of net periodic pension costs (see "Note 12. Employee Benefit Plans" for additional details).