Share-Based Compensation - Expense Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	$ 4,861	$ 3,724	$ 4,190
Stock Options Compensation Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	1,448	1,053	958
Nonvested Stock Awards Compensation Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	3,206	2,459	2,935
Employee Stock Purchase Plan Compensation Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	84	89	88
Matching Stock Contribution 401 K Plan Compensation Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	0	0	72
Directors Stock Ownership Plan Compensation Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based Compensation Expense	$ 123	$ 123	$ 137