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Stockholders' Equity and Stock-based Compensation (Restricted Stock) (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Nov. 02, 2019
Dec. 21, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock-based employee compensation     $ 34,892 $ 30,090 $ 26,961  
Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of shares granted (in shares)     595,985 548,245 1,326,849  
Weighted-average grant date fair value (usd per share)     $ 81.59 $ 75.44 $ 42.69  
Units vested and released in period (in shares)     438,892 525,375 368,367  
Units outstanding and expected to vest (in shares)     1,214,818 1,226,883 1,410,588 587,333
Unrecognized employee compensation cost, period for recognition     2 years 7 months 6 days      
Share-based Compensation Award, Tranche Two | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Award vesting period 3 years 3 years