Accounting policies - Disaggregated revenue (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Total Revenue	$ 32,479,158	$ 44,237,263	$ 72,168,548	$ 77,106,253
Contracts in progress.
Net Income (Loss)	15,850,257	7,323,771	22,324,605	11,137,397
Income from operations	$ 5,010,790	$ 9,479,634	$ 12,324,784	$ 14,007,970
Increase in basic earnings	$ 0.27	$ 0.48	$ 0.71	$ 0.74
Increase in diluted earnings	$ 0.26	$ 0.47	$ 0.70	$ 0.73
Retail revenue [Member]
Total Revenue	$ 8,181,884	$ 7,573,329	$ 16,806,822	$ 15,344,424
Bulk revenue [Member]
Total Revenue	8,447,958	8,482,495	16,790,052	17,486,868
Services revenue [Member]
Total Revenue	11,922,469	24,093,963	29,340,080	36,815,664
Services revenue [Member] | Transferred over Time [Member]
Total Revenue	3,988,174	19,839,950	13,385,268	28,428,534
Services revenue [Member] | Transferred at Point in Time [Member]
Total Revenue	7,934,295	4,254,013	15,954,812	8,387,130
Manufacturing revenue [Member]
Total Revenue	3,926,847	4,087,476	9,231,594	7,459,297
Construction Sevices [Member]
Total Revenue	3,324,610	19,827,827	12,528,274	28,521,342
Operations and Maintenance [Member]
Total Revenue	7,068,922	4,044,015	14,168,275	7,729,821
Design and Consulting Services [Member]
Total Revenue	$ 1,528,937	$ 222,121	$ 2,643,531	$ 564,501