Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Summary of Stock Option Activity) (Details)

v3.6.0.2
Stock-Based Compensation (Summary of Stock Option Activity) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]        
Options outstanding, beginning, number of shares 2,288,870 2,640,785 3,148,264  
Granted, number of shares 430,544 500,761 512,761  
Cancelled, number of shares (117,699) (172,018) (102,598)  
Exercised, number of shares (450,173) (680,658) (917,642)  
Options outstanding, ending, number of shares 2,151,542 2,288,870 2,640,785 3,148,264
Options outstanding, beginning, weighted average exercise price $ 32.69 $ 28.00 $ 25.02  
Granted, weighted average exercise price 56.63 48.46 39.69  
Cancelled, weighted average exercise price 47.33 34.59 28.39  
Exercised, weighted average exercise price 29.25 25.63 24.28  
Options outstanding, ending, weighted average exercise price $ 37.40 $ 32.69 $ 28.00 $ 25.02
Options outstanding, beginning, weighted average remaining contractual life, years 6 years 4 months 22 days 6 years 6 months 6 years 6 months 6 years 4 months 10 days
Options outstanding, ending, weighted average remaining contractual life, years 6 years 4 months 22 days 6 years 6 months 6 years 6 months 6 years 4 months 10 days
Options outstanding, beginning, aggregate intrinsic value $ 38,209 $ 43,682 $ 45,187  
Options outstanding, ending, aggregate intrinsic value $ 45,253 $ 38,209 $ 43,682 $ 45,187
Options vested and expected to vest, number of shares 2,086,456      
Options vested and expected to vest, weighted average exercise price $ 36.95      
Options vested and expected to vest, weighted average remining contractual life, years 6 years 3 months 26 days      
Options vested and expected to vest, aggregate intrinsic value $ 44,798      
Options exercisable, number of shares 1,168,794      
Options exercisable, weighted average exercise price $ 28.63      
Options exercisable, weighted average remaining contractual life 4 years 10 months 25 days      
Options exercisable, aggregate intrinsic value $ 34,691