Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, January 31, 2016	$ (121.1)
Other comprehensive (loss) income before reclassifications	4.8
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss	(2.8)
Tax effects	(2.4)
Total other comprehensive (loss)	(0.4)	$ (2.7)
Balances, April 30, 2016	(121.5)
Net Unrealized Gains (Losses) on Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, January 31, 2016	15.7
Other comprehensive (loss) income before reclassifications	(4.5)
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss	(3.1)
Tax effects	(1.9)
Total other comprehensive (loss)	(9.5)
Balances, April 30, 2016	6.2
Net Unrealized Gains (Losses) on Available-for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, January 31, 2016	0.2
Other comprehensive (loss) income before reclassifications	2.9
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss	(0.1)
Tax effects	(0.5)
Total other comprehensive (loss)	2.3
Balances, April 30, 2016	2.5
Defined Benefit Pension Components
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, January 31, 2016	(28.3)
Other comprehensive (loss) income before reclassifications	(0.1)
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss	0.4
Tax effects	0.0
Total other comprehensive (loss)	0.3
Balances, April 30, 2016	(28.0)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, January 31, 2016	(108.7)
Other comprehensive (loss) income before reclassifications	6.5
Pre-tax (gains) losses reclassified from accumulated other comprehensive loss	0.0
Tax effects	0.0
Total other comprehensive (loss)	6.5
Balances, April 30, 2016	$ (102.2)