XML 41 R27.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation (Tables)
 9 Months Ended
Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Summary of Expense Related to Share-Based Payments
The table below summarizes the expense recognized related to share-based payments recognized for the three and nine month periods ended September 30 (in thousands): 
 
 
Three Months Ended
September 30,
 
Nine Months Ended
September 30,
 
 
2018
 
2017
 
2018
 
2017
Stock options
 
$
11,154

 
$
16,212

 
$
33,205

 
$
42,254

Restricted stock
 
9,548

 
8,443

 
21,002

 
26,643

Stock-based compensation
 
$
20,702


$
24,655


$
54,207


$
68,897
Summary of Total Unrecognized Compensation Cost Related to Stock-Based Compensation
The following table summarizes the Company’s total unrecognized compensation cost related to stock-based compensation as of September 30, 2018 (cost in thousands):
 
 
Unrecognized
Compensation
Cost
 
Weighted Average
Period of Expense
Recognition
(in Years)
Stock options
 
$
68,687

 
1.41
Restricted stock
 
13,456

 
0.53
Total
 
$
82,143

 
 
Summary of Changes in Number of Shares of Common Stock Under Option
The following summarizes the changes in the number of shares of common stock under option for the nine month period ended September 30, 2018 (shares/options and aggregate intrinsic value in thousands):
 
 
Shares
 
Weighted
Average
Exercise
Price
 
Options
Exercisable
at End of
Period
 
Weighted
Average
Exercise
Price of
Exercisable
Options
 
Weighted
Average Fair
Value of
Options
Granted 
During the Period
 
Aggregate
Intrinsic
Value
Outstanding at December 31, 2017
 
8,031

 
$
109.78

 
4,029

 
$
75.80

 
 
 
$
663,815

Granted
 
408

 
204.57

 
 
 
 
 
$
50.04

 
 
Exercised
 
(692
)
 
71.50

 
 
 
 
 
 
 
108,164

Forfeited
 
(40
)
 
149.22

 
 
 
 
 
 
 
 
Outstanding at September 30, 2018
 
7,707

 
$
118.03

 
4,588

 
$
91.27

 
 
 
$
846,395

Expected to vest as of September 30, 2018
 
7,707

 
$
118.03

 
 
 
 
 
 
 
 
Schedule of Weighted-Average Assumptions
The fair value of stock option awards granted was estimated using the Black-Scholes option pricing model with the following weighted-average assumptions for grants or modifications during the nine month periods ended September 30, 2018 and 2017:
 
 
September 30,
 
 
2018
 
2017
Risk-free interest rate
 
2.57
%
 
1.65
%
Dividend yield
 
—

 
—

Expected volatility
 
26.93
%
 
28.02
%
Expected life (in years)
 
3.8

 
3.4
Summary of Changes in Number of Shares of Restricted Stock and Restricted Stock Units
The following table summarizes the changes in the number of shares of restricted stock and restricted stock units for the nine months ended September 30, 2018 (shares in thousands): 
 
 
Shares
 
Weighted
Average
Grant Date
Fair Value
Outstanding at December 31, 2017
 
365

 
$
155.58

Granted
 
104

 
190.18

Vested
 
(49
)
 
157.66

Canceled or forfeited
 
(26
)
 
157.39

Outstanding at September 30, 2018
 
394

 
$
173.21