Income Tax Expense Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense [Abstract]
Federal Classified as Operating Expense	$ (1,931)	$ (1,277)	$ 1,782
Federal Classified as Other Utility Income	287	434	385
Federal Classified as Other Income - Land Sales and Donations	175	17	57
Federal Classified as Other Income - Non-Water Sales	328	774	702
Federal Classified as Other Income - Other	(857)	503	(686)
Total Federal Income Tax Expense	(1,998)	451	2,240
State Classified as Operating Expense	(77)	(716)	788
Statet Classified as Other Utility Income	111	104	92
State Classified as Other - Land Sales and Donations	130	5	0
State Classified as Other - Non-Water Sales	141	175	172
State Classified as Other - Other	(489)	149	(126)
Total State Income Tax Expense	(184)	(283)	926
Total Income Tax Expense	$ (2,182)	$ 168	$ 3,166