Intangible assets - Costs and accumulated amortization (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Cost
Finite-Lived Intangible Assets, Gross	$ 5,430,000	$ 5,430,000
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization	(2,611,112)	(2,028,334)
Intangible assets, net	2,818,888	3,401,666
Non-compete agreement
Cost
Finite-Lived Intangible Assets, Gross	530,000	530,000
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization	(530,000)	(493,889)
Trade names
Cost
Finite-Lived Intangible Assets, Gross	2,700,000	2,700,000
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization	(920,000)	(740,000)
Facility management contracts
Cost
Finite-Lived Intangible Assets, Gross	2,200,000	2,200,000
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization	$ (1,161,112)	$ (794,445)