Commitments and contingencies (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 28, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies [Line Items]
Operating Leases, Rent Expense, Net		$ 870,833	$ 844,561	$ 834,738
Employment Agreement Base Annual Salaries		$ 2,000,000
Cayman Water Retail Operations, Percentage Of Gross Profit		54.00%	54.00%
Cayman Water Retail Operations, Percentage Of Revenue		39.00%	39.00%
Noncancellable Lease Term Expiration Date		2021
Long-term Purchase Commitment, Amount		$ 4,300,000
Revenues		65,719,857	$ 59,367,022
WSC [Member]
Commitments And Contingencies [Line Items]
Accounts Receivable, Net		$ 17,600,000	$ 9,100,000
North Sound Water Works Plant [Member]
Commitments And Contingencies [Line Items]
Expiry Date of Supply Agreement		2019-02
Red Gate Water Works Plant [Member]
Commitments And Contingencies [Line Items]
Expiry Date of Supply Agreement		2019-02
North Side Water Works Plant [Member]
Commitments And Contingencies [Line Items]
Expiry Date of Supply Agreement		2019-06
Revenues		$ 2,700,000
North Sound And Red Gate Plant [Member]
Commitments And Contingencies [Line Items]
Revenues		5,100,000
Energy Pass Through Charges [Member]
Commitments And Contingencies [Line Items]
Revenues		$ 3,200,000
Subsequent Event [Member] | North Side Water Works Plant [Member]
Commitments And Contingencies [Line Items]
Expiration Period Of Maintenance of Plant	7 years