Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

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,
	2017		2016		2017		2016
Stock options	$	243	$	215	$	714	$	632
Nonvested stock awards and restricted stock units		717		773		2,314		2,366
Employee stock purchase plan		22		21		66		64
Non-elective and elective 401(k) matching contribution in stock		8		473		72		1,749
Director stock ownership plan		34		37		103		131
Total stock-based compensation expense	$	1,024	$	1,519	$	3,269	$	4,942

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

Number of options granted	42,477
Dividend yield	1.49	%
Expected volatility	25.52	%
Risk-free interest rate	1.67	%
Expected term (years)	4.0