Stock-Based Compensation Plans (Schedule of Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	$ 389	$ 263	$ 124
Income tax benefit	84	57	27
Fair value of grants vested	302	149	0
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	751	916	762
Income tax benefit	161	197	164
Fair value of grants vested	780	931	702
Management Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	95	104	97
Income tax benefit	20	22	21
Fair value of grants vested	75	130	91
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	532	291	370
Income tax benefit	114	63	80
Fair value of grants vested	344	284	843
Deferred Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	110	106	97
Income tax benefit	24	23	21
Fair value of grants vested	$ 102	$ 105	$ 90

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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