Note 5 - Goodwill and Other Intangible Assets - Goodwill By Reportable Segment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Beginning Balance	$ 16,231,938	$ 14,404,618
Acquisitions	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
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
Acquisitions	0	1,997,174
Adjustments	221,111	(169,854)
Ending Balance	$ 15,974,793	$ 15,753,682