Income Taxes (Schedule of Income Tax Expense Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Tax at Statutory Rate	$ 12,007	$ 10,703	$ 9,786
Tax Effect of:
Utility Plant Related	(1,059)	(920)	(572)
State Income Taxes - Net	770	745	711
Employee Benefits	(5)	7	(6)
Other	22	16	18
Total Income Tax Expense	$ 11,735	$ 10,551	$ 9,937