Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

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,
	2019		2018		2019		2018
Stock options	$	173	$	266	$	433	$	518
Nonvested stock awards and restricted stock units		440		576		1,138		1,351
Employee stock purchase plan		24		22		47		44
Director stock ownership plan		23		28		54		62
Total share-based compensation expense	$	660	$	892	$	1,672	$	1,975