Share-Based Compensation - Expense Table (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 660	$ 892	$ 1,672	$ 1,975
Stock Options Compensation Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	173	266	433	518
Nonvested Stock Awards and Restricted Stock Unit Compensation Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	440	576	1,138	1,351
Employee Stock Purchase Plan Compensation Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	24	22	47	44
Directors Stock Ownership Plan Compensation Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 23	$ 28	$ 54	$ 62