XML 43 R25.htm IDEA: XBRL DOCUMENT v3.20.4
Stock Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based Payment Arrangement, Activity [Table Text Block]
Following is a summary of stock option activity for the year ended December 31, 2020, relating to the stock options awarded under the 2018 LTIP and the 2009 LTIP:
 SharesWeighted
Average
Exercise
Price		Weighted Average Remaining Contractual Term (Years)
Aggregate Intrinsic Value(a)
(In thousands)
Options outstanding at December 31, 2019
1,623,720 $25.30 7.22$22,836 
Granted424,500 42.23 
Exercised(422,820)23.43 
Forfeited— — 
Options outstanding at December 31, 2020
1,625,400 $30.21 7.28$22,882 
Options vested or expected to vest at December 31, 2020
1,580,805 $30.11 7.26$22,408 
Options exercisable at December 31, 2020
666,100 $23.91 5.84$13,577 
(a)Intrinsic value is defined as the amount by which the fair value of the underlying common shares exceeds the exercise price of the option.
Five Year Service Stock Options [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
The fair value of our five-year service-based stock options granted during the years ended December 31, 2020, 2019 and 2018 was established at the date of grant using the Black-Scholes pricing model, with the weighted average assumptions as follows:
 Year Ended December 31,
 202020192018
Risk-free interest rate1.42 %2.51 %2.72%
Expected volatility29.15 %28.81 %32.01%
Expected term (in years)5.65.95.7
Weighted average grant date fair value of options granted during the period$12.65$9.06$11.31