CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 98.2	$ 40.2	$ 164.7	$ 16.0
Other comprehensive income (loss), net of reclassifications:
Net loss on derivative instruments (net of tax effect of $2.3, ($1.7), $1.9 and ($2.0), respectively)	(19.5)	(4.3)	(15.5)	(1.0)
Change in net unrealized gain (loss) on available-for-sale debt securities (net of tax effect of zero, $0.1, $0.1 and ($0.3), respectively)	0.9	(0.2)	1.3	0.9
Change in defined benefit pension items (net of tax effect of zero, $0.4, zero and $0.5, respectively)	0.0	(1.8)	(0.3)	(2.4)
Net change in cumulative foreign currency translation gain (loss) (net of tax effect of ($0.4), ($0.4), ($0.4) and zero, respectively)	43.2	(22.8)	20.3	(33.2)
Total other comprehensive income (loss)	24.6	(29.1)	5.8	(35.7)
Total comprehensive income (loss)	$ 122.8	$ 11.1	$ 170.5	$ (19.7)