Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Assumptions Used To Determine Fair Value of Stock Options

The following assumptions were used to determine the fair value of stock options as of the grant date to determine compensation expense for the years ended December 31, 2017, 2016, and 2015:

Stock Options:	2017			2016			2015
Grant date fair value		$6.70			$6.31			$7.01
Expected life of options	8 years			8 years			8 years
Risk-free interest rate	2.29		%	2.15		%	2.17		%
Dividend yield rate	2.64		%	2.85		%	2.64		%
Price volatility	23.43		%	27.37		%	28.63		%

Stock Options Activity

The following table summarizes stock option activity during 2017: 

	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life, in Years
Outstanding at January 1, 2017	173,757			$23.65
Granted	26,112		33.03
Forfeited	(4,525	)	23.00
Exercised	(51,899	)	19.72
Outstanding at December 31, 2017	143,445			$26.79	5.60

Restricted Stock Unit Activity

The following table summarizes restricted stock unit activity during 2017:

	Number of Shares		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life, in Years
Outstanding at January 1, 2017	64,901			$28.04
Granted	23,967		33.12
Vested	(19,727	)	27.28
Forfeited	(3,258	)	28.28
Outstanding at December 31, 2017	65,883			$30.10	1.96