Hedging Instruments - Information on Location and Amounts of Derivative Gains and Losses in Condensed Consolidated Financial Statements (Detail) (Cash Flow Hedging [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2014		Jul. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	$ 1,987		$ (2,232)		$ 2,255		$ 3,238
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	3,868		2,407		9,365		3,289
Foreign Exchange Contract [Member] | Cost of sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	591		191		447		9,367
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	5,474	[1]	3,139	[1]	12,847	[1]	5,068	[1]
Put option contracts [Member] | Cost of sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	0		(8)		0		1,270
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	0	[1]	662	[1]	0	[1]	930	[1]
Precious Metal Forward Contracts [Member] | Cost of sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	1,396		(2,415)		1,808		(7,399)
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	(1,237)	[1]	(1,008)	[1]	(2,740)	[1]	(1,933)	[1]
Forward-starting interest rate swaps [Member] | Interest and other expenses, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	0		0		0		0
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	$ (369)	[2]	$ (386)	[2]	$ (742)	[2]	$ (776)	[2]

[1] The gain or loss recognized in earnings is included within Cost of sales.

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