Hedging Instruments - Additional Information (Details)	3 Months Ended		9 Months Ended
	Oct. 31, 2020 USD ($) oz	Oct. 31, 2019 USD ($)	Oct. 31, 2020 USD ($) oz		Oct. 31, 2019 USD ($)	Jul. 31, 2012 USD ($)
Derivative [Line Items]
Net gains reclassified from AOCI			$ 4,200,000
Net pre-tax derivative gains and losses			9,600,000
2012 4.40% Series B Notes, due July 2012
Derivative [Line Items]
Debt instrument face amount						$ 250,000,000.0
Forward-starting interest rate swaps | 2012 Debt Issuance
Derivative [Line Items]
Unrealized loss on interest rate swaps	$ 15,300,000		15,300,000
Forward-starting interest rate swaps | 2014 Debt Issuance
Derivative [Line Items]
Unrealized loss on interest rate swaps	$ 3,200,000		$ 3,200,000
Foreign exchange forward contracts | Maximum
Derivative [Line Items]
Term of contract (months)			12 months
Precious metal forward contracts
Derivative [Line Items]
Reclassified deferred hedging gains resulting from discontinuance of cash flow hedge			$ 4,200,000
Precious metal forward contracts | Maximum
Derivative [Line Items]
Term of contract (months)			18 months
Platinum
Derivative [Line Items]
Precious metal derivatives, ounces outstanding (ounces) | oz	21,900		21,900
Silver
Derivative [Line Items]
Precious metal derivatives, ounces outstanding (ounces) | oz	358,000		358,000
Gold
Derivative [Line Items]
Precious metal derivatives, ounces outstanding (ounces) | oz	67,400		67,400
Other income, net | Not Designated as Hedging Instrument
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	$ 2,900,000		$ 2,900,000
Cash Flow Hedging | Cost of sales | Forward-starting interest rate swaps
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	0	$ 0	0		$ 0
Cash Flow Hedging | Cost of sales | Foreign exchange forward contracts
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	(600,000)	(1,000,000.0)	(1,700,000)		(3,500,000)
Cash Flow Hedging | Cost of sales | Precious metal forward contracts
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	(1,800,000)	600,000	(7,300,000)	[1]	2,800,000
Cash Flow Hedging | Other income, net | Forward-starting interest rate swaps
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	0	0	0		0
Cash Flow Hedging | Other income, net | Foreign exchange forward contracts
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	0	0	0		0
Cash Flow Hedging | Other income, net | Precious metal forward contracts
Derivative [Line Items]
Pre-tax gains on derivatives not designated as hedging instruments	$ 0	$ 0	$ 0	[1]	$ 0

[1] Includes net gains of $4.2 million in the nine months ended October 31, 2020 reclassified from Accumulated OCI into Cost of sales on the Condensed Consolidated Statement of Earnings as a result of the discontinuation of hedge accounting on certain precious metal forward contracts.