Additional Information to Stock Options Exercised (Details) (Stock Options, USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Stock Options
     
Schedule Of Stock Options [Line Items]      
Intrinsic value $ 15,102 $ 14,515 $ 3,026
Exercise proceeds 20,211 22,112 8,991
Income tax benefit $ 4,383 $ 4,017 $ 511