XML 64 R39.htm IDEA: XBRL DOCUMENT v3.10.0.1
Equity Based Compensation Plans (Tables)
 12 Months Ended
Dec. 31, 2018
Share-based Compensation [Abstract]  
Weighted average assumptions used to estimate fair value of stock options
The fair value of stock options was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions used for grants:

 
2018
 
2017
 
2016
Stock price
$
262.09

 
$
240.56

 
$
219.60

Risk-free interest rates
2.76
%
 
2.30
%
 
2.08
%
Expected lives
6 years

 
6 years

 
6 years

Volatility
24.89
%
 
24.10
%
 
26.47
%
Dividend yield
2.81
%
 
2.90
%
 
2.89
%
Summary of stock options activity
A summary of the status of the Company’s stock option plans as of December 31, 2018, 2017, and 2016 and changes during the years ended on those dates is presented below:

 
2018
 
2017
 
2016
 
Shares
 
Weighted-
average
exercise
price
 
Shares
 
Weighted-
average
exercise
price
 
Shares
 
Weighted-
average
exercise
price
Outstanding at beginning of year
536,208

 
$
211.41

 
557,648

 
$
181.50

 
525,094

 
$
154.98

Granted
119,361

 
262.09

 
164,677

 
240.56

 
207,429

 
219.60

Exercised
(39,175
)
 
159.05

 
(176,489
)
 
146.86

 
(138,054
)
 
138.79

Forfeited and canceled
(3,440
)
 
221.80

 
(9,628
)
 
160.40

 
(36,821
)
 
178.18

Outstanding at end of year
612,954

 
224.57

 
536,208

 
211.41

 
557,648

 
181.50

Options exercisable at year end
322,837

 
206.63

 
223,796

 
191.09

 
290,340

 
160.90
Restricted stock activity
The following table summarizes information about restricted stock outstanding as of December 31, 2018, 2017 and 2016 and changes during the years ended:
 
2018
 
2017
 
2016
 
Shares
 
Weighted-
average
grant
price
 
Shares
 
Weighted-
average
grant
price
 
Shares
 
Weighted-
average
grant
price
Unvested at beginning of year
90,823

 
$
163.49

 
58,349

 
$
149.11

 
54,676

 
$
147.10

Granted
51,945

 
194.70

 
62,706

 
177.28

 
49,183

 
150.13

Vested
(48,212
)
 
150.76

 
(29,675
)
 
170.17

 
(38,427
)
 
147.12

Forfeited and canceled
(3,498
)
 
158.71

 
(557
)
 
119.37

 
(7,083
)
 
141.76

Unvested at end of year
91,058

 
180.99

 
90,823

 
163.49

 
58,349

 
149.11
Summary of long term incentive plan - Z Units
The following table summarizes information about the LTIP Units outstanding as of December 31, 2018:
 
Long Term Incentive Plan - LTIP Units
 
Total
Vested
Units
 
Total
Unvested
Units
 
Total
Outstanding
Units
 
Weighted-
average
Grant-date
Fair Value
 
Weighted-
average
Remaining
Contractual
Life (years)
Balance, December 31, 2015
144,185

 
106,157

 
250,342

 
$
75.41

 
9.5
Granted
—

 
—

 
—

 


 

Vested
36,842

 
(36,842
)
 
—

 


 

Converted
—

 
—

 
—

 


 

Cancelled
—

 
(9,288
)
 
(9,288
)
 


 

Balance, December 31, 2016
181,027

 
60,027

 
241,054

 
$
75.11

 
8.5
Granted
—

 
—

 
—

 


 

Vested
32,961

 
(32,961
)
 
—

 


 

Converted
(688
)
 
—

 
(688
)
 


 

Cancelled
—

 
(3,854
)
 
(3,854
)
 


 

Balance, December 31, 2017
213,300

 
23,212

 
236,512

 
$
75.03

 
7.5
Granted
—

 
—

 
—

 
 
 
 
Vested
12,051

 
(12,051
)
 
—

 
 
 
 
Converted
(91,270
)
 
—

 
(91,270
)
 
 
 
 
Cancelled
—

 
—

 
—

 
 
 
 
Balance, December 31, 2018
134,081

 
11,161

 
145,242

 
$
75.03

 
6.5