Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation and Employee Benefit Plans - Additional Information (Details Textuals)

v3.8.0.1
Stock-Based Compensation and Employee Benefit Plans - Additional Information (Details Textuals) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Feb. 28, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 5,500      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 1 year 9 months      
Allocated Share-based Compensation Expense $ 8,473 $ 5,474    
Shares Issued upon Settlement of Employee Bonus Plan     300,000  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value $ 2,100 1,900    
Preferred Stock, Shares Authorized 25,000,000     25,000,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans 0      
Proceeds from Stock Options Exercised $ 1,000 400    
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options 2,100 $ 300    
Accrued Bonuses $ 1,800      
Equity Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 13,874,903      
ESPP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 2,406,646      
Restricted Stock Unit and Restricted Stock Award [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 23.42      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 2 years 3 months 29 days      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized $ 47,700      
Employee Stock Option [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 2 years 3 months 29 days      
Common Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common Stock, Shares Authorized 550,000,000     550,000,000
Common Class A [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common Stock, Shares Authorized 441,124,000     441,124,000
Common Class B [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common Stock, Shares Authorized 493,430,000     493,430,000