CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015
Current assets:
Allowance for doubtful accounts	$ 2,642	$ 2,524
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
Common stock:
Treasury stock, at cost (in shares)	1,365,885	1,609,958
Common Class A [Member]
Common stock:
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)	16,603,729	16,152,405
Common Class B [Member]
Common stock:
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)	3,537,366	3,537,298