Note 5 - Goodwill and Other Intangible Assets, Net - Goodwill By Reportable Segment (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Beginning Balance	$ 16,231,938	$ 14,404,618	$ 14,404,618
Acquisitions	0	2,000,000.0	1,997,174
Adjustments	221,111		(169,854)
Ending Balance	16,453,049		16,231,938
Commercial Air Handling [Member]
Beginning Balance	478,256	478,256	478,256
Acquisitions	0		0
Adjustments	0		0
Ending Balance	478,256		478,256
Industrial and Transportation Products [Member]
Beginning Balance	15,753,682	$ 13,926,362	13,926,362
Acquisitions	0		1,997,174
Adjustments	221,111		(169,854)
Ending Balance	$ 15,974,793		$ 15,753,682