Revenue Recognition from Contracts with Customers (Schedule of Operating Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Regulated Tariff Sales
Residential	$ 15,980	$ 15,623
Commercial	3,309	3,109
Industrial	2,198	2,312
Fire Protection	3,013	2,888
Wholesale	3,339	3,212
Non-Regulated Contract Operations	2,824	3,999
Total Revenue from Contracts with Customers	30,663	31,143
Other Regulated Revenues	58	62
Other Non-Regulated Revenues	102	101
Inter-segment Elimination	(125)	(129)
Total Revenue	$ 30,698	$ 31,177