Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (210.9)	$ (256.0)
Other comprehensive income (loss) before reclassifications	(5.0)
Pre-tax losses reclassified from accumulated other comprehensive loss	(1.4)
Tax effects	(0.2)
Total other comprehensive loss	(6.6)	(10.0)
Ending balance	(245.3)	(128.6)
Net Unrealized Gains (Losses) on Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	15.0
Other comprehensive income (loss) before reclassifications	4.3
Pre-tax losses reclassified from accumulated other comprehensive loss	(0.7)
Tax effects	(0.3)
Total other comprehensive loss	3.3
Ending balance	18.3
Net Unrealized Gains (Losses) on Available-for-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	3.3
Other comprehensive income (loss) before reclassifications	1.5
Pre-tax losses reclassified from accumulated other comprehensive loss	0.0
Tax effects	(0.4)
Total other comprehensive loss	1.1
Ending balance	4.4
Defined Benefit Pension Components
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(16.3)
Other comprehensive income (loss) before reclassifications	0.0
Pre-tax losses reclassified from accumulated other comprehensive loss	(0.7)
Tax effects	0.1
Total other comprehensive loss	(0.6)
Ending balance	(16.9)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(137.0)
Other comprehensive income (loss) before reclassifications	(10.8)
Pre-tax losses reclassified from accumulated other comprehensive loss	0.0
Tax effects	0.4
Total other comprehensive loss	(10.4)
Ending balance	(147.4)
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(135.0)	(123.8)
Ending balance	$ (141.6)	$ (133.8)