Debt (Details)				6 Months Ended
	Jul. 31, 2013 USD ($)	Jul. 31, 2013 CNY	Jul. 31, 2013 Credit Agreement [Member] USD ($)	Jul. 31, 2013 Total Credit Facilities [Member] USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period				3.45%
Line of Credit Facility, Remaining Borrowing Capacity			$ 94,593,000	$ 642,935,000
Line of Credit Facility, Amount Outstanding			57,083,000	207,412,000
Line of Credit Facility, Interest Rate at Period End			6.00%
Line of Credit Facility, Maximum Borrowing Capacity	$ 151,676,000	930,000,000