Description of Business, Basis of Presentation, Corporate Transactions, Significant Accounting Policies, and Recent Accounting Pronouncements - Corporate Transactions (Details)								1 Months Ended			3 Months Ended			12 Months Ended			16 Months Ended
	May 15, 2017 USD ($) mi² active_water_connection	Jun. 02, 2016 USD ($)	May 11, 2016 USD ($) shares	May 09, 2016 USD ($)	May 03, 2016 USD ($) $ / shares shares	Mar. 17, 2016 USD ($)	Jul. 14, 2015 USD ($)	Dec. 31, 2016 USD ($) shares	Apr. 30, 2015 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) mi²	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 16, 2016 USD ($)
Property, Plant and Equipment [Line Items]
Gross amount to be received from transfer of project agreement										$ 4,100,000
Proceeds from transfer of project agreement									$ 296,000								$ 2,800,000
Other income (expense)														$ 1,478,000	$ 2,222,000	$ 767,000
Remaining proceeds from transfer of project agreement														1,000,000
Proceeds from the condemnation of Valencia														0	0	55,107,000
Gain on condemnation of Valencia														0	0	42,983,000
Loss of disposal group recorded in other expense														0	54,000	176,000
Business combination, tax liability								$ 178,000						0	178,000
Deferred tax liabilities, gross								$ 18,793,000						$ 12,882,000	18,793,000
Area of certificated service areas | mi²														336
Transfer of Project Agreement
Property, Plant and Equipment [Line Items]
Other income (expense)																	$ 3,300,000
Valencia
Property, Plant and Equipment [Line Items]
Proceeds from the condemnation of Valencia							$ 55,000,000
Proceeds from additional working capital adjustments							$ 108,000
Gain on condemnation of Valencia												$ 43,000,000
Discontinued operation, tax effect of discontinued operation												$ 20,200,000
Growth premium receivable for each new water meter installed														$ 3,000
Period for maximum payout of growth premium receivable														20 years
Maximum payout of growth premium receivable														$ 45,000,000
Other income														1,400,000	1,200,000	$ 624,000
Willow Valley
Property, Plant and Equipment [Line Items]
Proceeds from sale of productive assets				$ 2,300,000
Loss of disposal group recorded in other expense											$ 54,000		$ 176,000
Eagletail Water Company
Property, Plant and Equipment [Line Items]
Active water connections | active_water_connection	55
Area of certificated service areas | mi²	8
Business combination, consideration transferred	$ 80,000
Business combination, assets acquired	80,000
Business combination, liabilities assumed	$ 78,000
GWR Global Water Resources Corp
Property, Plant and Equipment [Line Items]
Business combination, accounts payable					$ 731,000
Business compensation, deferred compensation					353,000
Business combination, tax liability					$ 1,400,000
Treasury stock retired (in shares) | shares								8,726,747
Sonoran Utility Services, LLC (“Sonoran”)
Property, Plant and Equipment [Line Items]
Liability assumed from acquisition						$ 2,800,000												$ 3,800,000
Reduction in acquisition liability						$ 1,000,000
Gain from acquisition liability recorded in other income															$ 954,000
Valencia Water Company
Property, Plant and Equipment [Line Items]
Deferred tax liabilities, gross														$ 7,200,000
IPO
Property, Plant and Equipment [Line Items]
Stock issued during period, new issues (in shares) | shares					1,164,800
Stock issued during period (in dollars per share) | $ / shares					$ 6.25
Proceeds from issuance initial public offering					$ 7,300,000
Underwriter
Property, Plant and Equipment [Line Items]
Proceeds from issuance initial public offering			$ 1,100,000
Maximum | Underwriter
Property, Plant and Equipment [Line Items]
Stock issued during period, new issues (in shares) | shares			174,720
Private Letter Ruling
Property, Plant and Equipment [Line Items]
Gain on condemnation of Valencia		$ 19,400,000