Notes Receivable and Customers' Advances for Construction (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Municipality Note	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Notes Receivable and Customers' Advances for Construction [Abstract]
Number of municipalities with agreements to extend water service | Municipality	3
Number of notes receivable repaid | Note	2
Interest income on notes receivable	$ 110	$ 107	$ 101
Interest rate on notes outstanding	7.50%
Amounts Related to Water District Projects Included in Balance Sheet [Abstract]
Notes receivable, including interest	$ 255	266
Customers' advances for construction	310	626
Other customers' advances for construction	$ 7,190	$ 10,086