Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Deferred Compensation Arrangements [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of each grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:

	2018	2017
Dividend yield	6.5%	5.3%
Expected volatility	19.4%	19.8%
Expected lives	2.9 years	2.9 years
Risk-free interest rate	2.39%	1.49%

Schedule of Stock Option Activity

The following table summarizes our outstanding stock options:

	Six Months Ended
	June 30,
	2018		2017
Options outstanding January 1,	859,182		541,679
Options granted under 2012 Plan	560,000		485,000
Options exercised under 2012 Plan	(94,170	)	(70,830	)
Options forfeited under 2012 Plan	(15,000	)	(6,668	)
Options exercised under 2005 Plan	—		(15,000	)
Options outstanding, June 30,	1,310,012		934,181
Exercisable at June 30,	854,990		540,830