Hedging Instruments - Additional Information (Details) $ in Millions	12 Months Ended
	Jan. 31, 2018 USD ($) oz
Derivative [Line Items]
Expected approximate amount of net pre-tax derivative gains included in accumulated other comprehensive income that will be reclassified into earnings within the next 12 months	$ 0.5
2012 4.40% Series B Notes, due July 2042 [Member]
Derivative [Line Items]
Debt Instrument, Face Amount	250.0
Interest Rate Swap [Member] | 2012 Debt Issuance [Member]
Derivative [Line Items]
Unrealized loss on interest rate swaps	18.5
Interest Rate Swap [Member] | 2014 Debt Issuance [Member]
Derivative [Line Items]
Unrealized loss on interest rate swaps	$ 3.7
Foreign Exchange Forward [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	12 months
Foreign Exchange Forward [Member] | Other expense (income), net [Domain] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (9.2)
Precious Metal Forward Contracts [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	17 months
Platinum [Member]
Derivative [Line Items]
Notional amount of precious metal hedge (in ounces) | oz	45,000
Silver [Member]
Derivative [Line Items]
Notional amount of precious metal hedge (in ounces) | oz	900,000
Gold [Member]
Derivative [Line Items]
Notional amount of precious metal hedge (in ounces) | oz	37,200