Stock Based Compensation (Tables)

6 Months Ended

Jun. 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				Six Months Ended
	June 30,				June 30,
	2017		2016		2017		2016
Stock options	$	244	$	216	$	471		417
Nonvested stock awards and restricted stock units		795		745		1,597		1,593
Employee stock purchase plan		21		20		44		43
Non-elective and elective 401(k) matching contribution in stock		—		587		64		1,276
Director stock ownership plan		32		57		69		94
Total stock-based compensation expense	$	1,092	$	1,625	$	2,245	$	3,423

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