Share-Based Compensation (Tables)

9 Months Ended

Sep. 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				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Stock options	$	267	$	243	$	785	$	714
Nonvested stock awards and restricted stock units		550		717		1,901		2,314
Employee stock purchase plan		24		22		68		66
Non-elective and elective 401(k) matching contribution in stock		—		8		—		72
Director stock ownership plan		31		34		93		103
Total share-based compensation expense	$	872	$	1,024	$	2,847	$	3,269

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