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, 2013		Jul. 31, 2012		Jul. 31, 2013		Jul. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	$ (2,232)		$ (27,582)		$ 3,238		$ (30,371)
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	2,407		(3,956)		3,289		(7,715)
Foreign exchange forward contracts [Member] | Cost of sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pre-Tax Gain (Loss) Gain Recognized in OCI (Effective Portion)	191		(3,824)		9,367		4,261
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	3,139	[1]	(1,732)	[1]	5,068	[1]	(4,313)	[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)	(8)		(308)		1,270		(409)
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	662	[1]	(6)	[1]	930	[1]	(129)	[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)	(2,415)		(4,800)		(7,399)		(7,712)
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	(1,008)	[1]	(2,084)	[1]	(1,933)	[1]	(3,139)	[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		(18,650)		0		(26,511)
Gain (Loss) Reclassified from Accumulated OCI into Earnings (Effective Portion)	$ (386)	[2]	$ (134)	[2]	$ (776)	[2]	$ (134)	[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.