Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Share Based Compensation [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
Stock options	$	266	$	244	$	518	$	471
Nonvested stock awards and restricted stock units		576		795		1,351		1,597
Employee stock purchase plan		22		21		44		44
Non-elective and elective 401(k) matching contribution in stock		—		—		—		64
Director stock ownership plan		28		32		62		69
Total share-based compensation expense	$	892	$	1,092	$	1,975	$	2,245

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

Number of options granted	35,842
Dividend yield	1.37	%
Expected volatility	24.73	%
Risk-free interest rate	2.54	%
Expected term (years)	4.0