Segment information - Revenues earned by major geographic region and major customer (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 68,793,651	$ 65,719,857
Cayman Island [Member]
Segment Reporting Information [Line Items]
Revenue	30,327,139	34,623,925
Bahamas [Member]
Segment Reporting Information [Line Items]
Revenue	23,114,860	23,241,361
Indonesia [Member]
Segment Reporting Information [Line Items]
Revenue	131	153,233
United States [Member]
Segment Reporting Information [Line Items]
Revenue	14,968,868	7,256,150
Revenues earned from management services agreement with OC-BVI [Member]
Segment Reporting Information [Line Items]
Revenue	382,653	445,188
Water and Sewerage Corporation [Member]
Segment Reporting Information [Line Items]
Revenue	$ 22,877,741	$ 22,956,878
Percentage of consolidated revenues	33.00%	35.00%
Water Authority - Cayman [Member]
Segment Reporting Information [Line Items]
Revenue	$ 3,871,248	$ 7,789,926
Percentage of consolidated revenues	6.00%	12.00%
One Customer [Member]
Segment Reporting Information [Line Items]
Revenue	$ 9,238,476	$ 5,008,473
Percentage of consolidated revenues	13.00%	8.00%