Commitments and Contingent Liabilities (Schedule of Purchased Water Costs) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Purchased Water
Treated	$ 795	$ 754	$ 1,574	$ 1,555
Untreated	573	570	1,232	1,236
Total Costs	$ 1,368	$ 1,324	$ 2,806	$ 2,791

Cost of water purchased, may include any water related assessment. If water is bought on a unit volume basis, would also be considered as commodity costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_CostOfPurchasedWater
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration