Stock Based Compensation (Tables)

9 Months Ended

Sep. 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				Nine Months Ended
	September 30,				September 30,
	2016		2015		2016		2015
Stock options	$	215	$	164	$	632	$	548
Nonvested stock awards and restricted stock units		773		668		2,366		2,179
Employee stock purchase plan		21		19		64		56
Non-elective and elective 401(k) matching contribution in stock		473		449		1,749		1,624
Director stock ownership plan		37		31		131		93
Total stock-based compensation expense	$	1,519	$	1,331	$	4,942	$	4,500

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