Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation and Employee Benefit Plans - Stock Options (Details 4)

v3.8.0.1
Stock-Based Compensation and Employee Benefit Plans - Stock Options (Details 4) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value $ 2,100 $ 1,900
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  
Proceeds from Stock Options Exercised $ 1,000 400
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options $ 2,100 $ 300
Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 3,069  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 0  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period 129  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares 5  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 2,935  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable [Table Text Block] 2899  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options 2,559  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price $ 8.95  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price 7.63  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price 8.99  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price 8.90  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price $ 8.07  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term 2 years 4 months 10 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value $ 40,641  
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  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value $ 40,413  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term 2 years 11 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value $ 37,767  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price $ 18.40