Income Taxes (Schedule of Income Tax Expense Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax at Statutory Rate	$ 7,204	$ 6,457	$ 7,009
Tax Effect of:
Utility Plant Related	(1,356)	(802)	422
Tangible Property Repairs	(11,298)	(10,156)	(7,763)
State Income Taxes - Net	1,364	1,173	1,207
Other	(33)	188	49
Total Income Tax (Benefit) Expense	$ (4,119)	$ (3,140)	$ 924