Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 67.3	$ (194.3)	$ (139.1)	$ (210.9)
Other comprehensive (loss) income before reclassifications			7.3	(9.8)
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss			(4.7)	(10.4)
Tax effects			1.3	(1.1)
Total other comprehensive (loss) income	(1.9)	14.4	3.9	(21.3)
Ending balance	69.3	(171.5)	69.3	(171.5)
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(154.5)	(170.7)	(160.3)	(135.0)
Ending balance	(156.4)	(156.3)	(156.4)	(156.3)
Net Unrealized Gains (Losses) on Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			8.4	15.0
Other comprehensive (loss) income before reclassifications			(8.3)	4.3
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss			(4.8)	(7.0)
Tax effects			1.5	(1.6)
Total other comprehensive (loss) income			(11.6)	(4.3)
Ending balance	(3.2)	10.7	(3.2)	10.7
Net Unrealized Gains on Available-for-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			4.7	3.3
Other comprehensive (loss) income before reclassifications			1.7	1.8
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss			0.1	0.0
Tax effects			0.1	(0.4)
Total other comprehensive (loss) income			1.9	1.4
Ending balance	6.6	4.7	6.6	4.7
Defined Benefit Pension Components
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(22.8)	(16.3)
Other comprehensive (loss) income before reclassifications			0.0	0.1
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss			0.0	(3.4)
Tax effects			0.0	0.8
Total other comprehensive (loss) income			0.0	(2.5)
Ending balance	(22.8)	(18.8)	(22.8)	(18.8)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(150.6)	(137.0)
Other comprehensive (loss) income before reclassifications			13.9	(16.0)
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss			0.0	0.0
Tax effects			(0.3)	0.1
Total other comprehensive (loss) income			13.6	(15.9)
Ending balance	$ (137.0)	$ (152.9)	$ (137.0)	$ (152.9)