Annual report pursuant to Section 13 and 15(d)

Capital Structure and Per Share Data (Details Textual)

v2.4.0.6
Capital Structure and Per Share Data (Details Textual) (USD $)
In Millions, except Share data, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Vote
Dec. 31, 2011
Dec. 31, 2010
Capital Structure and Per Share Data (Textual) [Abstract]      
Preferred stock shares authorized 3,000,000    
Number of classes of common stock 2    
Stated Interest rate on debt agreement 5.00% 5.00%  
Capital Structure and Per Share Data (Additional Textual) [Abstract]      
Preferred stock, issued 0 0  
Preferred stock, outstanding 0 0  
5.0% Convertible Senior Notes [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Stated Interest rate on debt agreement 5.00%    
Class A Convertible Preferred Stock [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Preferred stock shares authorized 300,000    
Preferred stock par value $ 0.10    
Class A convertible preferred stock redemption price $ 1,000    
Class A convertible preferred stock shares redeemed 13,802    
Series I Preferred Stock [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Class A Convertible Preferred Stock Shares Authorized 100,000    
Series II Preferred Stock [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Class A Convertible Preferred Stock Shares Authorized 100,000    
Series III Preferred Stock [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Class A Convertible Preferred Stock Shares Authorized 100,000    
Common Class A [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Common stock, par value $ 0.01 $ 0.01  
Common stock, shares authorized 100,000,000 100,000,000  
Common stock, number of votes per share 1    
Number of shares of class A common stock issuable against each share of class B common stock 1    
Authorized amount expend on repurchase of shares $ 395.0    
Common stock class A, shares repurchased 20,100,000    
Common stock class A, share repurchase price per share $ 16.46    
Remaining authorized amount $ 49.6    
Antidilutive stock options excluded in computation of diluted earnings per share 1,000,000 1,900,000 2,300,000
Common Class B [Member]
      
Capital Structure and Per Share Data (Textual) [Abstract]      
Common stock, par value $ 0.01 $ 0.01  
Common stock, shares authorized 30,000,000 30,000,000  
Common stock, number of votes per share 10