Note 13 - Segment and Related Information - Information by Industry Segment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Sales	$ 32,189,623	$ 26,397,857	$ 95,094,396	$ 76,841,745
Gross Profit	6,309,803	5,397,709	19,444,700	17,180,922
Operating Income	1,999,678	1,868,781	5,772,527	6,314,038
Pretax Income	1,762,198	1,491,400	4,998,959	6,754,815
Net Income	1,254,545	1,197,877	3,491,684	5,588,599
Commercial Air Handling [Member]
Sales	11,485,339	8,854,347	34,888,594	27,591,991
Gross Profit	2,558,998	1,420,320	7,641,794	5,681,179
Operating Income	1,522,819	291,729	4,467,716	2,182,452
Pretax Income	1,522,819	297,692	4,467,716	2,188,415
Net Income	1,088,816	223,269	3,194,417	1,641,311
Industrial and Transportation Products [Member]
Sales	20,704,284	17,543,510
Gross Profit	3,750,805	3,977,389
Operating Income	1,132,485	1,603,125
Pretax Income	986,173	1,734,115
Net Income	699,678	1,379,982
Aerospace [Member]
Sales			60,205,802	49,249,754
Gross Profit			11,802,906	11,499,037
Operating Income			4,254,106	4,687,388
Pretax Income			3,916,265	4,417,620
Net Income			2,717,548	3,471,748
Corporate and Other [Member]
Sales		0	95,094,396	76,841,745
Gross Profit	0	0	19,444,700	17,180,922
Operating Income	(655,626)	(26,073)	5,772,527	6,314,038
Pretax Income	(746,794)	(540,407)	4,998,959	6,754,815
Net Income	$ (533,949)	$ (405,374)	3,491,684	5,588,599
Industrial Hose [Member]
Sales			0	0
Gross Profit			0	706
Operating Income			(2,949,295)	(555,802)
Pretax Income			(3,385,022)	148,780
Net Income			$ (2,420,281)	$ 475,540