v3.7.0.1
Stock-Based Compensation (Classification Of Stock-Based Compensation) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation $ 13,375 $ 11,132 $ 25,938 $ 22,891
Cost Of Revenues [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation 1,802 1,747 3,537 3,588
Sales And Marketing [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation 1,457 1,457 2,886 3,090
Research And Development [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation 1,482 1,587 2,978 3,290
General And Administrative [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation $ 8,634 $ 6,341 $ 16,537 $ 12,923