Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Αllowancе for doubtful accounts (in Dollars)	$ 1,714	$ 1,678
Preferred stock par value (in Dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common Class A [Member]
Authorized Shares	90,000,000	90,000,000
Par Value (in Dollars per share)	$ 0.01	$ 0.01
Shares Issued	29,989,588	29,982,254
Shares Outstanding	27,567,971	27,560,637
Class Α - Sharеs hеld in trеasury	2,421,617	2,421,617
Common Class B [Member]
Authorized Shares	18,000,000	18,000,000
Par Value (in Dollars per share)	$ 0.01	$ 0.01
Shares Issued	8,039,524	8,039,524
Shares Outstanding	8,039,524	8,039,524