Accounting policies - Revenue recognized and billed on services (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Accounting policies
Revenue recognized to date on contracts in progress	$ 16,576,248	$ 6,109,396
Amounts billed to date on contracts in progress	(19,694,500)	(6,370,855)
Retainage	1,023,676	237,542
Net contract asset	(2,094,576)	(23,917)
Contract assets	1,658,912	489,961
Contract liabilities	(3,753,488)	(513,878)
Net contract liability	$ (2,094,576)	$ (23,917)