XML 54 R42.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stockholders' Equity - Summary of Assumptions Used to Value Stock Option Grants Using Lattice-Binomial Model (Details)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
$ / shares
Sep. 30, 2016
USD ($)
$ / shares
Sep. 30, 2017
USD ($)
$ / shares
Sep. 30, 2016
USD ($)
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment award, expiration period (in years)     10 years  
Dividend yield 0.00% 0.00% 0.00% 0.00%
Expected volatility 34.00% 41.00%    
Risk-free interest rate 2.24% 1.57%    
Suboptimal exercise factor 2.58 2.48   2.48
Weighted-average fair value (in dollars per share) | $ / shares $ 72.98 $ 44.68 $ 67.23 $ 47.79
Stock-based compensation expense $ 44,763 $ 43,495 $ 133,679 $ 130,029
Total income tax impact on provision (in thousands) $ 14,428 $ 16,294 $ 43,606 $ 48,828
Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected volatility     34.00% 41.00%
Risk-free interest rate     2.24% 1.57%
Suboptimal exercise factor     2.48  
Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected volatility     37.00% 50.00%
Risk-free interest rate     2.45% 2.04%
Suboptimal exercise factor     2.58