v3.7.0.1
Employee Stock-Based Compensation Share-based Compensation Equity Granted (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Employee stock-based compensation $ 6,534 $ 5,645  
2010 Equity Incentive Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum shares available 430,362    
2010 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted (shares) 402,000 418,000  
Weighted-average grant-date fair value (in dollars per share) $ 31.61 $ 21.79  
Common Class A [Member] | 2010 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted (shares) 286,908 236,973  
Accounting Standards Update 2016-09 [Member] | Retained Earnings [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Reduction to retained earnings     $ 1,800