Annual report pursuant to Section 13 and 15(d)

Share Based Compensation (Schedule Of Share-based Compensation, Stock Options, Activity) (Details)

v3.8.0.1
Share Based Compensation (Schedule Of Share-based Compensation, Stock Options, Activity) (Details) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]        
Stock Option, Outstanding as of December 31, 1,546,014 1,639,865 1,690,899 1,546,508
Stock Options, Granted, Number of Shares 1,013,893      
Stock Options, Exercised, Number of Shares 562,587 113,820 40,461  
Stock Options, Forfeited, Number of Shares 3,374 18,760 0  
Stock Options, Expired, Number of Shares 541,783 116,004 7,498  
Stock Options Weighted Average Exercise Price Outstanding $ 39.73 $ 63.09    
Stock Options, Granted, Weighted Average Exercise Price 41.69      
Stock Options, Exercised, Weighted Average Exercise Price 37.6      
Stock Options, Forfeited, Weighted Average Exercise Price 40.90      
Stock Options. Expired, Weighted Average Exercise Price $ 47.04      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number 1,031,581      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price $ 39.32