XML 63 R49.htm IDEA: XBRL DOCUMENT v3.6.0.2
Stockholders' Equity (Summary of Assumptions Used to Value Stock Option Grants) (Details)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2016
USD ($)
$ / shares
Dec. 31, 2015
USD ($)
$ / shares
Dec. 31, 2014
USD ($)
$ / shares
Stockholders' Equity Note [Abstract]      
Dividend yield 0.00% 0.00% 0.00%
Expected volatility, minimum 40.00% 36.00% 41.00%
Expected volatility, maximum 50.00% 53.00% 48.00%
Risk-free interest rate, minimum 1.57% 2.03% 2.39%
Risk-free interest rate, maximum 2.04% 2.29% 2.83%
Suboptimal exercise factor, minimum 2.48 2.47 2.66
Suboptimal exercise factor, maximum 2.48 2.48 5.44
Valuation data:      
Weighted-average fair value (in USD per share) | $ / shares $ 48.85 $ 39.22 $ 30.17
Total stock-based compensation expense (in thousands) $ 173,675 $ 124,725 $ 115,239
Total income tax impact on provision (in thousands) $ 65,173 $ 47,125 $ 43,999