XML 99 R79.htm IDEA: XBRL DOCUMENT v3.8.0.1
STOCK-BASED COMPENSATION - Fair Value Assumptions (Details) - Stock options - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Weighted-average assumptions used to estimate the fair value of options granted              
Dividend yield (as a percent)         0.00% 0.00% 0.00%
Expected volatility (as a percent)         36.50% 36.20% 37.10%
Risk-free interest rate (as a percent)         2.11% 1.57% 1.57%
Expected term         6 years 1 month 6 days 6 years 3 months 18 days 5 years 9 months 18 days
Stock Options, Number of Shares              
Balance at the beginning of the period (in shares)       22,643 22,643    
Granted (in shares) 77 12 26 1,319      
Exercised (in shares)         (5,754)    
Cancelled or forfeited (in shares)         (504)    
Balance at the end of the period (in shares) 17,819       17,819 22,643  
Vested and expected to vest in the future at the end of the period (in shares) 16,863       16,863    
Exercisable at the end of the period (in shares) 9,282       9,282    
Stock options, Weighted-Average Exercise Price Per Share              
Balance at the beginning of the period (in dollars per share)       $ 23.55 $ 23.55    
Granted (in dollars per share) $ 61.71 $ 56.08 $ 49.71 $ 45.94      
Exercised (in dollars per share)         9.15    
Cancelled or forfeited (in dollars per share)         40.09    
Balance at the end of the period (in dollars per share) 29.62       29.62 $ 23.55  
Vested and expected to vest in the future at the end of the period (in dollars per share) 28.81       28.81    
Exercisable at the end of the period (in dollars per share) $ 18.68       $ 18.68    
Weighted-Average Remaining Contractual Term              
Balance at the beginning of the period         6 years 1 month 6 days 5 years 9 months 18 days  
Balance at the end of the period         6 years 1 month 6 days 5 years 9 months 18 days  
Vested and expected to vest in the future at the end of the period         6 years    
Exercisable at the end of the period         4 years 4 months 24 days    
Aggregate Intrinsic Value              
Balance at the beginning of the period       $ 474,739 $ 474,739    
Balance at the end of the period $ 600,032       600,032 $ 474,739  
Vested and expected to vest in the future at the end of the period 581,425       581,425    
Exercisable at the end of the period $ 414,052       $ 414,052