Derivatives And Financial Instruments (Schedule Of Classification Of Gains And Losses On Derivative Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012		Apr. 30, 2011
Derivatives, Fair Value [Line Items]
Recognized in Other Comprehensive Income (Loss)	$ 223		$ 4,631
Reclassified from Accumulated Other Comprehensive Income into Statement of Operations	278	[1]	2,229	[1]
Recognized in Other Income (Expense), Net	(181)		(1,872)
Derivatives Designated As Hedging Instruments [Member] | Foreign Currency Forward [Member]
Derivatives, Fair Value [Line Items]
Recognized in Other Comprehensive Income (Loss)	223		4,631
Reclassified from Accumulated Other Comprehensive Income into Statement of Operations	278	[1]	2,229	[1]
Recognized in Other Income (Expense), Net	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Currency Forward [Member]
Derivatives, Fair Value [Line Items]
Recognized in Other Comprehensive Income (Loss)	0		0
Reclassified from Accumulated Other Comprehensive Income into Statement of Operations	0	[1]	0	[1]
Recognized in Other Income (Expense), Net	$ (181)		$ (1,872)

[1] Amounts reclassified from accumulated other comprehensive income into the statement of operations are classified as operating expenses.