Commitments and contingencies (Details Textual)	12 Months Ended
	Dec. 31, 2015 USD ($) gal	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 29, 2011 gal
Commitments And Contingencies [Line Items]
Operating Leases, Rent Expense, Net	$ 821,845	$ 812,658	$ 822,159
Employment Agreement Base Annual Salaries	2,100,000
Goodwill	$ 3,499,037	$ 3,499,037
Cayman Water Retail Operations, Percentage Of Gross Profit	55.00%	53.00%	52.00%
Cayman Water Retail Operations, Percentage Of Revenue	40.00%	36.00%	36.00%
Noncancellable Lease Term Expiration Date	2035
Long-term Purchase Commitment, Amount	$ 1,200,000
Operating Income (Loss)	8,468,064	$ 6,461,059	$ 7,661,576
Property, plant and equipment, net	$ 53,743,170	56,396,988
Long-term Purchase Commitment, Date	Dec. 31, 2018
Cw Bahamas [Member]
Commitments And Contingencies [Line Items]
Delivery Terms Volume Of Water Per Week | gal	63,000,000
Cw Belize [Member]
Commitments And Contingencies [Line Items]
Delivery Terms, Volume of water per day | gal				450,000
CW-Bahamas Windsor Plant [Member]
Commitments And Contingencies [Line Items]
Revenue, Net	$ 5,800,000	6,200,000	7,200,000
Delivery Terms Volume Of Water Per Week | gal	16,800,000
CW Bali [Member]
Commitments And Contingencies [Line Items]
Plant Capacity | gal	790,000
Operating Income (Loss)	$ (484,000)	$ (458,000)	$ (438,000)
Property, plant and equipment, net	$ 3,000,000