CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Statement of Comprehensive Income [Abstract]
Net gain (loss) on derivative instruments, tax effect	$ (0.7)	$ 0.5
Change in net unrealized gain on available-for-sale debt securities, tax effect	0.1	(0.3)
Change in defined benefit pension items, tax effect	(1.4)	0.0
Net change in cumulative foreign currency translation (loss) gain, tax effect	$ 0.3	$ (0.3)