CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Statement of Comprehensive Income [Abstract]
Net (loss) on derivative instruments, tax effect	$ 0.2	$ 0.0	$ (0.6)	$ (0.7)
Change in net unrealized gain (loss) on available-for-sale securities, tax effect	0.0	0.0	(0.6)	0.2
Change in defined benefit pension items, tax effect	0.0	0.0	(0.2)	0.0
Net change in cumulative foreign currency translation loss, tax effect	$ (0.5)	$ (4.5)	$ (0.5)	$ 0.0