Derivative Instruments and Foreign Currency Exposure (Details) (USD $)	3 Months Ended		9 Months Ended
	Oct. 31, 2013 Not Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Oct. 31, 2012 Not Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Oct. 31, 2013 Not Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Oct. 31, 2012 Not Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Oct. 31, 2013 Designated as Hedging Instrument [Member] Foreign Currency Cash Flow Hedge [Member]	Oct. 31, 2012 Designated as Hedging Instrument [Member] Foreign Currency Cash Flow Hedge [Member]	Jan. 31, 2013 Designated as Hedging Instrument [Member] Foreign Currency Cash Flow Hedge [Member]
Notional Value in USD	$ 1,000	$ 11,175	$ 6,587	$ 36,501
Gain and loss reported in current operating income (expense)	(42)	205	81	261
Notional Value in USD					412,440		6,944,040
Gain reported in equity as other comprehensive income					(59,078)		38,513
Gain reclassifed from other comprehensive income into current earnings during three months ended October 31, 2013, reported in operating income					$ 85	$ 33