Note J - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020
Total Net Sales	$ 23,524,600	$ 40,975,320
Net Sales	23,524,600	40,975,320
Operating profit (loss)	(1,140,953)	262,936
Corporate expenses	735,000	627,000
Interest expense	5,953
Interest and other income	(4,323)	(6,335)
Total earnings (loss) before taxes	(1,136,630)	269,271
Segment assets	71,248,119		$ 77,344,088
Coil [Member]
Total Net Sales	15,432,784	28,181,468
Net Sales	15,432,784	28,181,468
Tubular [Member]
Total Net Sales	8,091,816	12,793,852
Net Sales	8,091,816	12,793,852
Operating Segments [Member]
Operating profit (loss)	(400,000)	890,000
Segment assets	55,059,000		59,554,000
Operating Segments [Member] | Coil [Member]
Total Net Sales	15,433,000	28,181,000
Net Sales	15,433,000	28,181,000
Operating profit (loss)	(459,000)	345,000
Segment assets	32,271,000		35,895,000
Operating Segments [Member] | Tubular [Member]
Total Net Sales	8,092,000	12,794,000
Net Sales	8,092,000	12,794,000
Operating profit (loss)	59,000	$ 545,000
Segment assets	22,788,000		23,659,000
Corporate, Non-Segment [Member]
Segment assets	$ 16,189,000		$ 17,790,000