Consolidated Balance Sheets Parentheticals (USD $)	Mar. 31, 2015	Dec. 31, 2014
Class A Common Stock, $0.01 par value, one vote per share; 180,000,000 shares authorized at March 31, 2015 and December 31, 2014; 65,797,851 and 65,632,309 shares issued and 53,075,305 and 52,938,267 shares outstanding (net of 12,722,546 and 12,694,042 shares in treasury) on March 31, 2015 and December 31, 2014, respectively
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	180,000,000	180,000,000
Common Stock, Shares, Issued	65,797,851	65,632,309
Common Stock, Shares, Outstanding	53,075,305	52,938,267
Treasury Stock, Shares	12,722,546	12,694,042
Class B Common Stock, $0.01 par value, ten votes per share; 30,000,000 shares authorized at March 31, 2015 and December 31, 2014; 945,485 and 1,020,485 shares issued and outstanding on March 31, 2015 and December 31, 2014, respectively
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	945,485	1,020,485
Common Stock, Shares, Outstanding	945,485	1,020,485