CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) (USD $)	Oct. 31, 2011	Jan. 31, 2011
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock, (in shares)	1,503,849	1,721,601
Common Class A [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	71,000,000	71,000,000
Common stock, shares issued (in shares)	14,146,418	14,146,416
Common Class B [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	4,000,000	4,000,000
Common stock, shares issued (in shares)	3,536,609	3,536,604