Hedging Instruments (Details Textual) (USD $)	3 Months Ended	9 Months Ended
	Oct. 31, 2011	Oct. 31, 2011
Hedging Instruments Additional (Textual)
Gain related to net unrealized gains and interest receivable before tax	$ 9,527,000	$ 9,527,000
Notional amount of interest rate swap agreements outstanding as fair value hedges	60,000,000	60,000,000
Notional amount of foreign exchange forward contracts as cash flow hedges	144,600,000	144,600,000
Notional amount of foreign exchange forward contracts as undesignated hedges	27,178,000	27,178,000
Expected approximate amount of net pre-tax derivative gains included in accumulated other comprehensive income that will be reclassified into earnings within the next 12 months		15,033,000
Put Option [Member]
Hedging Instruments (Textual)
Notional amount of Outstanding Put Option contracts	$ 0	$ 0
Platinum [Member]
Hedging Instruments (Textual)
Derivative instrument Outstanding	34,900	34,900
Silver [Member]
Hedging Instruments (Textual)
Derivative instrument Outstanding	806,600	806,600