Hedging Instruments - Additional Information (Details) ¥ in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2016 JPY (¥) oz	Jul. 31, 2016 USD ($) oz
Derivative Instruments, Gain (Loss) [Line Items]
Expected approximate amount of net pre-tax derivative losses included in accumulated other comprehensive income that will be reclassified into earnings within the next 12 months				$ (16.6)
Currency Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Term of Contract				Oct. 01, 2024
Derivative, Notional Amount						¥ 10,600.0	$ 100.0
Platinum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of precious metal hedge (in ounces) | oz						72,000	72,000
Silver [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of precious metal hedge (in ounces) | oz						1,380,000	1,380,000
Gold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of precious metal hedge (in ounces) | oz						47,500	47,500
Maximum [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Term of Contract				12 months
Maximum [Member] | Precious Metal Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Term of Contract				24 months
2012 4.40% Series B Notes, due July 2042 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Debt Instrument, Face Amount							$ 250.0
2012 Debt Issuance [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on interest rate swaps							20.4
2014 Debt Issuance [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on interest rate swaps							$ 3.9
Interest and other expenses, net [Domain] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	[1]	$ (1.9)	$ 3.9	$ (7.6)	$ 0.9

[1] The gain or loss recognized in earnings is included within Interest and other expenses, net.