Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Allowance for doubtful accounts (in Dollars)	$ 2,226	$ 2,064
Common Class B [Member]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	56,902,996	56,503,759
Common stock, par value (in Dollars per share)
Common Class A [Member]
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	7,331,574	7,331,574
Common stock, par value (in Dollars per share)
Class B Treasury Stock [Member]
Treasury stock, shares	4,739,462	4,739,462
Class A Treasury Stock [Member]
Treasury stock, shares	1,578,554	1,578,554