Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2013	Jan. 31, 2013	Apr. 30, 2012
Allowance for doubtful accounts receivable	$ 35,585	$ 45,947	$ 31,480
Preferred stock, shares authorized	1,000,000	1,000,000	1,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	80,000,000	80,000,000	80,000,000
Common stock, shares issued	20,735,127	20,616,957	20,461,840
Treasury stock, shares	492,225	492,225	492,225