v3.5.0.2
Employee Benefits and Share-Based Compensation - Stock Option Activity (Details) - 2009 Plan - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Number of Shares          
Outstanding at December 31, 2015 (in shares)     2,688    
Granted (in shares)     512    
Exercised (in shares)     (352)    
Expired (in shares)     (5)    
Forfeited (in shares)     (100)    
Outstanding at September 30, 2016 (in shares) 2,743   2,743   2,688
Exercisable at September 30, 2016 (in shares) 1,368   1,368    
Vested and expected to vest at June 30, 2016 (in shares) 2,597   2,597    
Weighted Average Exercise Price          
Outstanding at December 31, 2015 (in dollars per share)     $ 22.89    
Granted (in dollars per share)     29.25    
Exercised (in dollars per share)     19.24    
Expired (in dollars per share)     28.75    
Forfeited (in dollars per share)     29.74    
Outstanding at September 30, 2016 (in dollars per share) $ 24.30   24.30   $ 22.89
Exercisable at September 30, 2016 (in dollars per share) 19.36   19.36    
Vested and expected to vest at September 30, 2016 (in dollars per share) $ 23.99   $ 23.99    
Weighted-average remaining years, outstanding (in years)     7 years   6 years 10 months 20 days
Weighted-average remaining years, exercisable at September 30, 2016 (in years)     5 years 2 months    
Weighted-average remaining years, vested and expected to vest at September 30, 2016 (in years)     6 years 11 months    
Aggregate Intrinsic Value, outstanding at September 30, 2016 $ 38,482   $ 38,482    
Aggregate Intrinsic Value, exercisable at September 30, 2016 25,929   25,929    
Aggregate Intrinsic Value, vested and expected to vest at September 30, 2016 $ 37,230   $ 37,230    
Employee Stock Option          
Weighted Average Exercise Price          
Weighted-average fair value (in dollars per share) $ 10.32 $ 10.51 $ 8.82 $ 10.57  
Intrinsic value of options exercised $ 2,100 $ 3,100 $ 5,000 $ 9,700  
Unrecognized compensation cost of unvested stock options $ 10,100   $ 10,100    
Weighted average period of compensation cost recognized     2 years 295 days