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Stock-Based Compensation (Details) (Stock Option Plan [Member], USD $)
 3 Months Ended 12 Months Ended
Mar. 31, 2014
Dec. 31, 2013
Stock Option Plan [Member]
    
Summary the stock option transactions    
Number of Options Outstanding at January 1, 2014 233,787  
Number of Options Exercised (7,294)  
Number of Options Outstanding at March 31, 2014 226,493 233,787
Number of Options Vested and Exercisable at March 31, 2014 226,493  
Weighted Average Exercise Price, Outstanding at January 1, 2014 $ 33.38  
Weighted Average Exercise Price, Exercised $ 34.80  
Weighted Average Exercise Price, Outstanding at March 31, 2014 $ 33.33 $ 33.38
Weighted Average Exercise Price Vested and Exercisable at March 31, 2014 $ 33.33  
Weighted Average Remaining Contractual Term (Years) 1 year 10 months 24 days 2 years 1 month 6 days
Weighted Average Remaining Contractual Term (Years) Vested and Exercisable 1 year 10 months 24 days  
Aggregate Intrinsic Value Outstanding at January 1, 2014 $ 4,058,035  
Aggregate Intrinsic Value Outstanding at March 31, 2014 3,814,944 4,058,035
Aggregate Intrinsic Value Vested and Exercisable at March 31, 2014 $ 3,814,944