Condensed Consolidated Balance Sheets (unaudited) (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Allowance for doubtful accounts (in Dollars)	$ 223	$ 244
Preferred stock, par value (in Dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in Shares)	2,000,000	2,000,000
Preferred stock, shares issued (in Shares)	0	0
Common Class A [Member]
Common stock, par value (in Dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in Shares)	60,000,000	60,000,000
Common stock, shares issued (in Shares)	25,249,029	25,129,776
Common stock, shares outstanding (in Shares)	20,732,784	20,624,976
Treasury stock, shares (in Shares)	4,516,245	4,504,800
Common Class B [Member]
Common stock, par value (in Dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in Shares)	80,000,000	80,000,000
Common stock, shares issued (in Shares)	4,208,118	4,188,296
Common stock, shares outstanding (in Shares)	3,455,411	3,437,496
Treasury stock, shares (in Shares)	752,707	750,800