CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 155.6	$ 66.5
Other comprehensive (loss) income, net of reclassifications:
Net gain on derivative instruments (net of tax effect of $(1.7) and $(0.4), respectively)	10.0	4.0
Change in net unrealized gain on available-for-sale debt securities (net of tax effect of zero and $0.1, respectively)	4.0	0.4
Change in defined benefit pension items (net of tax effect of zero and zero, respectively)	0.1	(0.3)
Net change in cumulative foreign currency translation gain (loss) (net of tax effect of $(1.8) and zero, respectively)	10.1	(22.9)
Total other comprehensive income (loss)	24.2	(18.8)
Total comprehensive income	$ 179.8	$ 47.7