Accounting policies - Disaggregated revenue (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total Revenue	$ 72,628,126	$ 68,793,651
Contracts in progress
Number of days after consumption billings are considered past due	45 days
Bahamas [Member]
Total Revenue	$ 21,654,153	$ 23,114,860
Minimum [Member]
Contracts in progress
Number of days after consumption billings are collected	30 days
Maximum [Member]
Contracts in progress
Number of days after consumption billings are collected	35 days
Percentage Of Bad Debts	1.00%	1.00%
Retail revenue [Member]
Total Revenue	$ 22,952,370	$ 26,456,022
Bulk revenue [Member]
Total Revenue	24,312,546	26,986,108
Services revenue [Member]
Total Revenue	12,937,859	1,759,446
Manufacturing revenue [Member]
Total Revenue	$ 12,425,351	$ 13,592,075