Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2016

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,
	2016		2015		2016		2015
Stock options	$	216	$	199	$	417	$	384
Nonvested stock awards and restricted stock units		745		759		1,593		1,511
Employee stock purchase plan		20		19		43		37
Non-elective and elective 401(k) matching contribution in stock		587		476		1,276		1,175
Director stock ownership plan		57		31		94		62
Total stock-based compensation expense	$	1,625	$	1,484	$	3,423	$	3,169

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

	2016
Number of options granted	67,444
Dividend yield	1.49	%
Expected volatility	28.39	%
Risk-free interest rate	1.08	%
Expected term (years)	4.0