Financing Arrangements (Details) (USD $)	3 Months Ended
	Apr. 30, 2012	Jan. 31, 2012	Apr. 30, 2011
Financing Arrangements [Abstract]
Borrowing capacity under line of credit	$ 10,500,000
Maturity date of the line of credit	9/1/2012
Line of credit prime interest rate percentage	4.00%
Letters of credit issued, amount	1,342,000
Borrowing outstanding under line of credit	0	0	0
Remaining borrowing capacity under the line of credit	$ 9,158,000