CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 66.5	$ (24.2)
Other comprehensive income (loss), net of reclassifications:
Net gain on derivative instruments (net of tax effect of ($0.4) and ($0.3), respectively)	4.0	3.3
Change in net unrealized gain on available-for-sale debt securities (net of tax effect of $0.1 and ($0.4), respectively)	0.4	1.1
Change in defined benefit pension items (net of tax effect of zero and $0.1, respectively)	(0.3)	(0.6)
Net change in cumulative foreign currency translation loss (net of tax effect of zero and $0.4, respectively)	(22.9)	(10.4)
Total other comprehensive loss	(18.8)	(6.6)
Total comprehensive income (loss)	$ 47.7	$ (30.8)