XML 63 R40.htm IDEA: XBRL DOCUMENT v3.10.0.1
Equity Incentive Awards (Tables)
 12 Months Ended
Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]
A summary of our restricted stock activities and related information is as follows: 
 
Number of Shares
 
Weighted Average Grant Date Fair Value Per Share
Balance at December 31, 2015
85,500

 
$49.72
Shares granted
133,717

 
$68.21
Shares vested
(153,610
)
 
$59.85
Balance at December 31, 2016
65,607

 
$63.68
Shares granted
130,426

 
$76.25
Shares forfeited
(990
)
 
$80.54
Shares vested
(125,271
)
 
$68.79
Balance at December 31, 2017
69,772

 
$77.77
Shares granted
192,505

 
$86.01
Shares vested
(112,426
)
 
$81.48
Balance at December 31, 2018
149,851

 
$85.56
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions
The fair value of stock options granted was estimated on the grant date using the Black-Scholes-Merton model. The following table includes the assumptions made in the valuation:                
 
2018
 
2017
 
2016
Dividend Yield
2.5%
 
2.4%
 
2.3%
Risk-free interest rate
2.8%
 
1.9%
 
1.3%
Expected Life
5.6 years
 
5.5 years
 
6 years
Expected Volatility
16.7%
 
17.8%
 
19.8%
         Weighted Average Grant Date Fair Value Per Share
$12.95
 
$11.00
 
$10.70
Summary of Stock Option Activity

No options were forfeited or expired during the years ended December 31, 2018, 2017 and 2016. A summary of our stock option activity and related information is as follows: 
 
Shares Subject To Options
 
Weighted Average
Exercise Price Per Share
 
Weighted Average Outstanding Contractual Life
(in years)
 
Average Intrinsic Value (in millions)
Balance at December 31, 2015
865,600

 
$23.12
 
1.5
 
$37.7
Options issued
7,550

 
$74.53
 
 
 
 
Options exercised
(440,000
)
 
$25.66
 
 
 
$18.7
Balance at December 31, 2016
433,150

 
$21.44
 
1.7
 
$22.0
Options issued
6,930

 
$81.15
 
 
 
 
Options exercised
(220,000
)
 
$22.05
 
 
 
$14.5
Balance at December 31, 2017
220,080

 
$22.72
 
1.6
 
$14.6
Options issued
6,270

 
$89.65
 
 
 
 
Options exercised
(202,800
)
 
$18.85
 
 
 
$16.9
Balance at December 31, 2018
23,550

 
$73.89
 
7.3
 
$0.5
Exercisable at December 31, 2018
17,084

 
$68.94
 
6.7
 
$0.5