CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Statement of Comprehensive Income [Abstract]
Net (loss) on derivative instruments, tax effect	$ 1.1	$ 0.8	$ (0.8)	$ (0.7)
Change in net unrealized gain (loss) on available-for-sale securities, tax effect	(0.1)	0.0	(0.6)	0.2
Change in defined benefit pension items, tax effect	(0.2)	0.0	(0.2)	0.0
Net change in cumulative foreign currency translation loss, tax effect	$ 0.0	$ 0.1	$ 0.0	$ 4.5