Acquisitions Net Assets Acquired (Details) - USD ($)		3 Months Ended
	May 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Cash and cash equivalents		$ 20,173,000	$ 5,248,000	$ 7,838,000	$ 20,498,000
Accounts receivable — net		1,776,000	1,528,000
Property, Plant and Equipment, Net		211,685,000	213,459,000
Property, plant and equipment		288,363,000	289,051,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		76,678,000	75,592,000
Accounts payable		366,000	321,000
Accrued Liabilities, Current		9,269,000	7,252,000
Goodwill			$ 0
Payments to Acquire Businesses, Gross	$ 2,800,000
Turner Ranches Water and Sanitation Company [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		176,000
Accounts receivable — net		121,000
Property, Plant and Equipment, Net		4,495,000
Property, plant and equipment		92,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		(3,751,000)
Accounts payable		(30,000)
Accrued Liabilities, Current		(46,000)
Assets		1,057,000
Goodwill		1,743,000
Payments to Acquire Businesses, Gross	$ 2,800,000	$ 2,800,000