Fair Value of Financial Instruments - Financial Assets and Liabilities Carried at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2015		Jan. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, Fair Value	$ 77,538		$ 79,790
Total financial liabilities, Fair Value	5,254		1,898
Other assets, net [Member] | Marketable securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	53,545	[1]	51,781	[1]
Short-term Investments [Member] | Bank Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	1,500	[2]	21,257	[2]
Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	15,070	[3]	6,699	[3]
Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	250	[3]	53	[3]
Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	118	[4]	246	[4]
Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	3,150	[4]	1,652	[4]
Accounts payable and accrued liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	7,173	[3]
Derivative Liability, Fair Value	1,986	[4]
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, Fair Value	77,538		79,790
Total financial liabilities, Fair Value	5,254		1,898
Carrying Value [Member] | Other assets, net [Member] | Marketable securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	53,545	[1]	51,781	[1]
Carrying Value [Member] | Short-term Investments [Member] | Bank Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	1,500	[2]	21,257	[2]
Carrying Value [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	15,070	[3]	6,699	[3]
Carrying Value [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	250	[3]	53	[3]
Carrying Value [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	118	[4]	246	[4]
Carrying Value [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	3,150	[4]	1,652	[4]
Carrying Value [Member] | Accounts payable and accrued liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	7,173	[3]
Derivative Liability, Fair Value	1,986	[4]
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, Fair Value	55,045		73,038
Total financial liabilities, Fair Value	0		0
Level 1 [Member] | Other assets, net [Member] | Marketable securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	53,545	[1]	51,781	[1]
Level 1 [Member] | Short-term Investments [Member] | Bank Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	1,500	[2]	21,257	[2]
Level 1 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]	0	[3]
Level 1 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]	0	[3]
Level 1 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	0	[4]	0	[4]
Level 1 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	0	[4]	0	[4]
Level 1 [Member] | Accounts payable and accrued liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]
Derivative Liability, Fair Value	0	[4]
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, Fair Value	22,493		6,752
Total financial liabilities, Fair Value	5,254		1,898
Level 2 [Member] | Other assets, net [Member] | Marketable securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	0	[1]	0	[1]
Level 2 [Member] | Short-term Investments [Member] | Bank Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	0	[2]	0	[2]
Level 2 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	15,070	[3]	6,699	[3]
Level 2 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	250	[3]	53	[3]
Level 2 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	118	[4]	246	[4]
Level 2 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	3,150	[4]	1,652	[4]
Level 2 [Member] | Accounts payable and accrued liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	7,173	[3]
Derivative Liability, Fair Value	1,986	[4]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, Fair Value	0		0
Total financial liabilities, Fair Value	0		0
Level 3 [Member] | Other assets, net [Member] | Marketable securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	0	[1]	0	[1]
Level 3 [Member] | Short-term Investments [Member] | Bank Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets, Fair Value	0	[2]	0	[2]
Level 3 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]	0	[3]
Level 3 [Member] | Prepaid expenses and other current assets [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]	0	[3]
Level 3 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	0	[4]	0	[4]
Level 3 [Member] | Accounts payable and accrued liabilities [Member] | Cash Flow Hedging [Member] | Precious Metal Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value	0	[4]	0	[4]
Level 3 [Member] | Accounts payable and accrued liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Fair Value	0	[3]
Derivative Liability, Fair Value	$ 0	[4]

[1] Included within Other assets, net.

[2] Included within Short-term investments.

[3] Included within Prepaid expenses and other current assets.

[4] Included within Accounts payable and accrued liabilities.