Income Taxes (Schedule of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (188)	$ 2,090	$ 7,305
State	2,073	1,066	877
Deferred:
Federal	(338)	7,713	3,325
State	(545)	310	307
Investment Tax Credits	(78)	(79)	(79)
Total Income Tax Expense	$ 924	$ 11,100	$ 11,735