Note G - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Total Net Sales	$ 40,975,320	$ 48,193,318
Operating profit (loss)	262,936	4,699,738
Interest and other income	(6,335)	(62,775)
Earnings before income taxes	269,271	4,762,513
Segment assets	83,504,005		$ 86,601,982
Coil [Member]
Total Net Sales	28,181,468	31,129,200
Tubular [Member]
Total Net Sales	12,793,852	17,064,118
Operating Segments [Member]
Operating profit (loss)	890,000	5,500,000
Segment assets	72,313,000		74,624,000
Operating Segments [Member] | Coil [Member]
Total Net Sales	28,181,000	31,129,000
Operating profit (loss)	345,000	3,179,000
Segment assets	39,583,000		43,104,000
Operating Segments [Member] | Tubular [Member]
Total Net Sales	12,794,000	17,064,000
Operating profit (loss)	545,000	2,321,000
Segment assets	32,730,000		31,520,000
Corporate, Non-Segment [Member]
Corporate expenses	627,000	$ 800,000
Segment assets	$ 11,191,000		$ 11,978,000