Financing Arrangements (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2015	Apr. 15, 2015	Apr. 14, 2015	Oct. 31, 2014
Line of Credit Facility [Line Items]
Unamortized Debt Issuance Expense	$ 489
Wells Fargo Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under line of credit			$ 10,500
Maturity date of the line of credit	Apr. 15, 2015
Letters of credit issued, amount	$ 850
Borrowing outstanding under line of credit	$ 0			$ 0
Remaining borrowing capacity under the line of credit				$ 9,650
JPMorgan Chase Bank [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date	Apr. 15, 2015
Borrowing capacity under line of credit		$ 125,000
Maturity date of the line of credit	Apr. 15, 2020
Borrowing outstanding under line of credit	$ 0
Remaining borrowing capacity under the line of credit	$ 125,000